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Sample records for noyes mn niagara

  1. Noyes, MN Natural Gas Exports to Canada

    Gasoline and Diesel Fuel Update (EIA)

    478,368 447,079 544,135 401,717 238,970 324,613 1996-2014 Pipeline Prices 4.21 4.49 4.15 2.86 3.87 5.59...

  2. Noyes, MN Natural Gas Exports to Canada

    Gasoline and Diesel Fuel Update (EIA)

    Thousand Cubic Feet) Dollars per Thousand Cubic Feet) North Troy, VT Natural Gas Pipeline Imports From Canada (Dollars per Thousand Cubic Feet) Decade Year-0 Year-1 Year-2 Year-3 Year-4 Year-5 Year-6 Year-7 Year-8 Year-9 1990's 3.00 2.96 2.75 2.27 2000's NA NA NA - = No Data Reported; -- = Not Applicable; NA = Not Available; W = Withheld to avoid disclosure of individual company data. Release Date: 08/31/2016 Next Release Date: 09/30/2016 Referring Pages: U.S. Price of Thousand Cubic

  3. NIAGARA FALLS STORAGE SITE

    Office of Legacy Management (LM)

    :i" _,, ' _~" ORISE 95/C-70 :E : i:; :' l,J : i.: RADIOLOGICAL SURVEY Op BUILDINGS 401, ' 403, AND ' m HITTMAN BUILDING $ <,' 2:. NIAGARA FALLS STORAGE SITE I .~~ ; " LEWISTON, ' NEW YORK : f? j:,:i I ,.J- ;b f" /: Li _e.*. ~,, I ,,~, ,:,,;:, Prepared by T. .I. Vitkus i,c Environmental Survey and Site Assessment Program Energy/Environment Systems Division ;>::; Oak Ridge Institute for Science and Education .,:, "Oak Ridge, Temressee 37831-0117 .F P ., ? :_ &,d

  4. Niagara Falls, New York: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Niagara Falls, New York: Energy Resources (Redirected from Niagara Falls, NY) Jump to: navigation, search Equivalent URI DBpedia Coordinates 43.0944999, -79.0567111 Show Map...

  5. American Ref-Fuel of Niagara Biomass Facility | Open Energy Informatio...

    Open Energy Info (EERE)

    Niagara Biomass Facility Jump to: navigation, search Name American Ref-Fuel of Niagara Biomass Facility Facility American Ref-Fuel of Niagara Sector Biomass Facility Type Municipal...

  6. Noyes, MN Natural Gas Imports by Pipeline from Canada

    Gasoline and Diesel Fuel Update (EIA)

    447,079 544,135 401,717 238,970 324,613 229,043 1996-2015 Pipeline Prices 4.49 4.15 2.86 3.87 5.59 2.88

  7. PP-190 Niagara Mohawk Power Corporation | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    190 Niagara Mohawk Power Corporation PP-190 Niagara Mohawk Power Corporation Presidential permit authorizing Niagara Mohawk Power Corporation to construct, operate, and maintain electric transmission facilitates at the U.S-Canadian border. PP-190 Niagara Mohawk Power Corporation (21.94 KB) More Documents & Publications PP-230-2 International Transmission Company Proposed Open Access Requirement for International Electric Transmission Facilities and Delegation to the Federal Energy Regulatory

  8. DOE - Office of Legacy Management -- Niagara VP_FUSRAP

    Office of Legacy Management (LM)

    Niagara Falls Vicinity Properties, New York, Site FUSRAP Site Niagara Falls Vicinity Properties Map Background-The Niagara Falls Vicinity Properties Site was remediated under the Formerly Utilized Sites Remedial Action Program (FUSRAP). FUSRAP was established in 1974 to remediate sites where radioactive contamination remained from Manhattan Project and early U.S. Atomic Energy Commission operations. History-Niagara Falls Storage Site Vicinity Properties, located near Lewiston, New York, consists

  9. U.S. Natural Gas Exports to Mexico

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    MI St. Clair, MI Noyes, MN Warroad, MN Babb, MT Havre, MT Port of Morgan, MT Sherwood, ND Pittsburg, NH Buffalo, NY Grand Island, NY Massena, NY Niagara Falls, NY Waddington, NY...

  10. Niagara Falls, New York: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    New York's 28th congressional district.12 Registered Energy Companies in Niagara Falls, New York Canrom Photovoltaics Inc References US Census Bureau Incorporated...

  11. EIS-0153: Niagara Import Point Project

    Broader source: Energy.gov [DOE]

    The Federal Energy Regulatory Commission prepared this statement to assess the environmental impacts of the proposed Niagara Import Point project that would construct an interstate natural gas pipeline to transport gas from Canada and domestic sources to the Northeastern United States market. The U.S. Department of Energy's Office of Fossil Energy was a cooperating agency during statement development and adopted this statement on 6/15/1990.

  12. Niagara County, New York: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    York Niagara, New York North Tonawanda, New York Olcott, New York Pendleton, New York Porter, New York Ransomville, New York Rapids, New York Royalton, New York Somerset, New York...

  13. Mr. Frank Archer President Niagara Cold Drawn Steel Corporation

    Office of Legacy Management (LM)

    Department of Energy Washington, DC 20585 FEB 2 1 1991 ' i-. 1,; ' -, f ' + \ 1 : , .J p- * c - Mr. Frank Archer President Niagara Cold Drawn Steel Corporation 110 Hopkins Street P.O. Box 399 Buffalo, NY 14240 Dear Mr. Archer: I have executed the consent forms for the performance of a radiological survey of the Niagara Cold Drawn Steel Corporation's property under the Formerly Utilized Sites Remedial Action Program (FUSRAP) of the U.S. Department of Energy (DOE). I enclose a copy of the consent

  14. Niagara Falls Storage Site, Lewiston, New York: geologic report

    SciTech Connect (OSTI)

    Not Available

    1984-06-01

    This report is one of a series of engineering and environmental reports planned for the US Department of Energy's properties at Niagara Falls, New York. It describes the essential geologic features of the Niagara Falls Storage Site. It is not intended to be a definitive statement of the engineering methods and designs required to obtain desired performance features for any permanent waste disposal at the site. Results are presented of a geological investigation that consisted of two phases. Phase 1 occurred during July 1982 and included geologic mapping, geophysical surveys, and a limited drilling program in the vicinity of the R-10 Dike, planned for interim storage of radioactive materials. Phase 2, initiated in December 1982, included excavation of test pits, geophysical surveys, drilling, observation well installation, and field permeability testing in the South Dike Area, the Northern Disposal Area, and the K-65 Tower Area.

  15. Niagara Falls Storage Site environmental monitoring report. Calendar year 1983

    SciTech Connect (OSTI)

    Not Available

    1984-07-01

    During 1983, an environmental monitoring program was continued at the Niagara Falls Storage Site, a United States Department of Energy (DOE) surplus facility located in Niagara County, New York presently used for the storage of radioactive residues, contaminated soils and rubble. The monitoring program at NFSS measures radon concentrations in air, uranium and radium concentrations in surface water, groundwater, and sediments, and external gamma exposure rates. Radiation doses to the public are also calculated. Environmental samples collected are analyzed to determine compliance with applicable standards. Comparison of 1983 monitoring results with 1982 results shows a significant decrease in radon levels at almost every monitoring location. External gamma exposure rates also showed a general decrease. 9 references, 10 figures, 11 tables

  16. Noyes, MN Natural Gas Pipeline Exports to Canada (Dollars per Thousand

    U.S. Energy Information Administration (EIA) Indexed Site

    Cubic Feet) Decade Year-0 Year-1 Year-2 Year-3 Year-4 Year-5 Year-6 Year-7 Year-8 Year-9 1990's NA NA 2000's NA NA 1.99 5.43 5.77 -- -- -- -- -- 2010's -- 3.90 3.46 3.83 11.05 3.34

  17. Noyes, MN Natural Gas Pipeline Exports to Canada (Dollars per Thousand

    U.S. Energy Information Administration (EIA) Indexed Site

    Cubic Feet) Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2011 4.54 4.21 4.89 4.12 4.30 4.58 4.46 4.09 4.00 3.56 3.57 3.37 2012 2.93 2.80 2.20 2.15 2.34 2.55 3.03 2.90 2.94 3.59 4.03 3.77 2013 3.77 3.63 4.04 4.38 4.27 4.17 3.91 3.61 3.88 3.74 4.04 4.59 2014 5.98 17.87 6.88 4.86 4.56 4.62 4.09 3.85 4.71 3.15 2015 3.29 4.03 3.93 2.81 2.95 3.87 3.43 4.03 4.02 3.08 2.06 2.19 2016 2.42 2.14 1.90 1.68 1.76 2.09

  18. Noyes, MN Natural Gas Pipeline Exports to Canada (Million Cubic Feet)

    U.S. Energy Information Administration (EIA) Indexed Site

    Decade Year-0 Year-1 Year-2 Year-3 Year-4 Year-5 Year-6 Year-7 Year-8 Year-9 1990's NA NA 2000's NA NA 71 172 2,193 0 0 0 0 0 2010's 0 3,975 11,768 16,209 5,474 5,245

  19. Noyes, MN Natural Gas Pipeline Exports to Canada (Million Cubic Feet)

    U.S. Energy Information Administration (EIA) Indexed Site

    Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2011 30 721 666 32 13 31 23 39 41 494 1,069 818 2012 1,273 1,377 647 277 236 107 168 105 54 342 3,941 3,242 2013 6,162 4,355 1,720 76 171 316 1,331 449 445 44 374 767 2014 1,648 2,476 282 245 205 0 84 410 6 118 2015 1,060 598 544 121 422 294 319 274 262 669 325 356 2016 616 546 422 330 344 614

  20. Noyes, MN Natural Gas Pipeline Imports From Canada (Dollars per Thousand

    U.S. Energy Information Administration (EIA) Indexed Site

    Cubic Feet) Decade Year-0 Year-1 Year-2 Year-3 Year-4 Year-5 Year-6 Year-7 Year-8 Year-9 1990's 2.40 2.46 2.07 2.29 2000's 3.75 4.19 3.09 5.04 5.77 8.01 6.82 6.72 8.48 4.21 2010's 4.49 4.15 2.86 3.87 5.59 2.88

  1. Noyes, MN Natural Gas Pipeline Imports From Canada (Dollars per Thousand

    U.S. Energy Information Administration (EIA) Indexed Site

    Cubic Feet) Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2011 4.58 4.37 4.22 4.21 4.36 4.47 4.33 4.09 3.92 3.65 3.64 3.50 2012 3.18 2.88 2.50 2.16 2.40 2.51 2.98 2.95 2.90 3.48 3.95 3.73 2013 3.74 3.65 3.98 4.12 4.08 3.84 3.79 3.44 3.54 3.62 3.77 4.45 2014 5.97 11.88 10.97 4.77 4.55 4.61 4.16 3.90 3.95 3.86 4.40 3.97 2015 3.34 4.03 3.35 2.75 2.79 2.75 2.76 2.86 2.75 2.62 2.39 2.29 2016 2.58 2.29 1.93 1.91 1.83 2.06

  2. Noyes, MN Natural Gas Pipeline Imports From Canada (Million Cubic Feet)

    U.S. Energy Information Administration (EIA) Indexed Site

    Decade Year-0 Year-1 Year-2 Year-3 Year-4 Year-5 Year-6 Year-7 Year-8 Year-9 1990's 394,415 395,650 468,576 506,866 2000's 469,361 448,898 402,621 359,801 399,298 467,595 419,284 499,863 476,948 478,368 2010's 447,079 544,135 401,717 238,970 324,613 229,043

  3. Noyes, MN Natural Gas Pipeline Imports From Canada (Million Cubic Feet)

    U.S. Energy Information Administration (EIA) Indexed Site

    Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2011 51,290 42,870 51,863 44,224 45,529 52,162 52,689 50,964 45,400 51,659 27,118 28,368 2012 22,036 21,459 23,879 43,604 44,578 41,943 43,823 44,416 41,802 41,662 14,057 18,459 2013 15,693 13,380 14,460 20,624 33,889 31,352 11,189 13,944 20,155 24,353 17,445 22,486 2014 26,877 24,032 29,979 30,354 32,653 31,697 29,370 28,374 26,447 24,326 20,140 20,363 2015 21,353 18,703 14,104 16,080 18,999 19,502 20,535 21,111 21,232 19,202 20,100 18,124

  4. Noyes, MN Natural Gas Pipeline Exports to Canada (Million Cubic Feet)

    Gasoline and Diesel Fuel Update (EIA)

    Cubic Feet) Decade Year-0 Year-1 Year-2 Year-3 Year-4 Year-5 Year-6 Year-7 Year-8 Year-9 1990's NA NA 2000's NA NA 1.99 5.43 5.77 -- -- -- -- -- 2010's -- 3.90 3.46 3.83 11.05 3.34 Cubic Feet)

    Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2011 4.54 4.21 4.89 4.12 4.30 4.58 4.46 4.09 4.00 3.56 3.57 3.37 2012 2.93 2.80 2.20 2.15 2.34 2.55 3.03 2.90 2.94 3.59 4.03 3.77 2013 3.77 3.63 4.04 4.38 4.27 4.17 3.91 3.61 3.88 3.74 4.04 4.59 2014 5.98 17.87 6.88 4.86 4.56 4.62 4.09 3.85

  5. Noyes, MN Natural Gas Pipeline Imports From Canada (Million Cubic Feet)

    Gasoline and Diesel Fuel Update (EIA)

    Cubic Feet) Decade Year-0 Year-1 Year-2 Year-3 Year-4 Year-5 Year-6 Year-7 Year-8 Year-9 1990's 2.40 2.46 2.07 2.29 2000's 3.75 4.19 3.09 5.04 5.77 8.01 6.82 6.72 8.48 4.21 2010's 4.49 4.15 2.86 3.87 5.59 2.88 Cubic Feet)

    Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2011 4.58 4.37 4.22 4.21 4.36 4.47 4.33 4.09 3.92 3.65 3.64 3.50 2012 3.18 2.88 2.50 2.16 2.40 2.51 2.98 2.95 2.90 3.48 3.95 3.73 2013 3.74 3.65 3.98 4.12 4.08 3.84 3.79 3.44 3.54 3.62 3.77 4.45 2014 5.97 11.88

  6. Niagara Falls Storage Site Vicinity Properties in Lewiston, New York,

    Office of Legacy Management (LM)

    Niagara Falls Storage Site Vicinity Properties in Lewiston, New York, from 7983 through 7986 Depatfment of Energy Former Sites Restoration Division Oak Ridge Field Office July 7 992 I I I I I I I I I I I I I I I I I I I CONTENTS Figures .......................... Tables .......................... Abbreviations ....................... Acronyms ......................... 1.0 Introduction ..................... 2.0 Site History ..................... 3.0 Property Descriptions ................ 3.1 3.2

  7. ADDENDUM TO ACTION DESCRIPTION MEMORANDUM NIAGARA FALLS STORAGE SITE

    Office of Legacy Management (LM)

    ADDENDUM TO ACTION DESCRIPTION MEMORANDUM NIAGARA FALLS STORAGE SITE PROPOSED INTERIM REMEDIAL ACTIONS FOR FY 1983-85 ACCELERATED PROGRAM (1984 VICINITY PROPERTIES CLEANUP) Prepared by Environmental Research Division Argonne National Laboratory Argonne, Illinois July 1984 Prepared for U.S. Department of Energy Oak Ridge Operations Technical Services Division Oak Ridge, Tennessee CONTENTS Page SUMMARY OF PROPOSED ACTION AND RELATED ACTIVITIES ........... 1 HISTORY AND ENVIRONMENTAL SETTING

  8. New runners to boost peak output at Niagara Falls

    SciTech Connect (OSTI)

    Reason, J.

    1990-01-01

    Retrofitted Francis turbines will improve the value of power generated from Niagara Falls by increasing the peak output of the hydroturbine units at the Robert Moses hydroelectric plant. The computer-designed runners are expected to add 330 MW to the peak capacity of the 28-yr-old plant and significantly increase the efficiency at high flow rates. Next year, the first new runner will be retrofit to the highly instrumented Unit 4. If the retrofit unit meets it increased-performance expectations, the other 12 units will be upgraded between 1993 and 1998. The work is part of an overall expansion of the Niagara Power Project designed to made better use of the power value of Niagara river water, within the constraints of a treaty with Canada and the scenic value of the falls. These constraints, together with varying flows and heads, introduced enormous complexities into the selection and design of the new runners. The alterations being made to Unit 4, in addition to replacing the turbine runner, include modifying the draft tube-liners, increasing the wicket-gate stroke, replacing the turbine discharge ring (to accommodate longer blades), making various electrical modifications to the generator, and replacing the transformer. But the key to the retrofit is the computer-designed runner. Charles Grose, senior project manager, New York Power Authority, White Plains, NY, emphasizes that such computer design techniques were not available a few years ago; neither were the computer-controlled machining techniques necessary to manufacture the new runners. Other aspects of the upgrading that were analyzed include runner stability, resonance, shaft torsional stress, and runaway speed.

  9. Environmental surveillance plan for the Department of Energy's Niagara Falls Storage Site (NFSS), Lewiston, New York

    SciTech Connect (OSTI)

    Englert, J.P.; Hinnefeld, S.L.

    1981-09-09

    The Niagara Falls Storage Site (NFSS) is a United States Department of Energy owned facility used for the storage of low-level radioactive residues. The site occupies 190 acres of the former Lake Ontario Ordnance Works and is located in the Niagara County town of Lewiston, in western New York State. The city of Niagara Falls is approximately eight (8) miles south of the NFSS. The purpose of this report is to describe environmental monitoring programs presently operated by NLO, and to suggest programs and revisions which should be implemented as a result of NLO's remedial actions at the NFSS.

  10. Review of integrated resource bidding at Niagara Mohawk

    SciTech Connect (OSTI)

    Goldman, C.A.; Busch, J.F.; Kahn, E.P.; Stoft, S.S.; Cohen, S.

    1992-05-01

    In June 1988, the New York Public Service Commission (PSC) ordered the state's investor-owned utilities to develop competitive bidding programs that included both supply and demandside resource options. The New York State Energy Research Development Authority (NYSERDA), the New York Department of Public Service, and the Department of Energy's Integrated Resource Planning program asked Lawrence Berkeley Laboratory (LBL) to review the integrated bidding processes of two New York utilities, Niagara Mohawk and Consolidated Edison. This interim report focuses on Niagara Mohawk (NMPC). In terms of overall approach, our analysis is intended as a critical review of a large-scale experiment in competitive resource acquisition implemented by New York utilities at the direction of their state regulators. The study is not a formal impact or process evaluation. Based on priorities established jointly with project sponsors, the report focuses on selected topics: analysis of the two-stage scoring system used by NMPC, ways that the scoring system can be improved, an in-depth review of the DSM bidding component of the solicitation including surveys of DSM bidders, relationship between DSM bidding and other utility-sponsored DSM programs, and major policy issues that arise in the design and implementation of competitive resource procurements. The major findings of this report are: NMPC's solicitation elicited an impressive response from private power developers and energy service companies. In the initial ranking of bids, DSM projects were awarded significantly more points on price and environmental factors compared to supply-side bids. NMPC's scoring system gave approximately twice as much weight nominally to price as to non-price factors (850 vs. 460 points).

  11. Review of integrated resource bidding at Niagara Mohawk

    SciTech Connect (OSTI)

    Goldman, C.A.; Busch, J.F.; Kahn, E.P.; Stoft, S.S.; Cohen, S.

    1992-05-01

    In June 1988, the New York Public Service Commission (PSC) ordered the state`s investor-owned utilities to develop competitive bidding programs that included both supply and demandside resource options. The New York State Energy Research & Development Authority (NYSERDA), the New York Department of Public Service, and the Department of Energy`s Integrated Resource Planning program asked Lawrence Berkeley Laboratory (LBL) to review the integrated bidding processes of two New York utilities, Niagara Mohawk and Consolidated Edison. This interim report focuses on Niagara Mohawk (NMPC). In terms of overall approach, our analysis is intended as a critical review of a large-scale experiment in competitive resource acquisition implemented by New York utilities at the direction of their state regulators. The study is not a formal impact or process evaluation. Based on priorities established jointly with project sponsors, the report focuses on selected topics: analysis of the two-stage scoring system used by NMPC, ways that the scoring system can be improved, an in-depth review of the DSM bidding component of the solicitation including surveys of DSM bidders, relationship between DSM bidding and other utility-sponsored DSM programs, and major policy issues that arise in the design and implementation of competitive resource procurements. The major findings of this report are: NMPC`s solicitation elicited an impressive response from private power developers and energy service companies. In the initial ranking of bids, DSM projects were awarded significantly more points on price and environmental factors compared to supply-side bids. NMPC`s scoring system gave approximately twice as much weight nominally to price as to non-price factors (850 vs. 460 points).

  12. Measurement of polycyclic aromatic hydrocarbons in the air along the niagara river

    SciTech Connect (OSTI)

    Hoff, R.M.; Chan, K.W.

    1987-06-01

    Two week-long studies in 1982-1983 have measure ambient concentrations of polycyclic aromatic hydrocarbons (PAH) and phthalate esters in air in both the particulate and gas phase along the US-Canadian border and the Niagara River. Concentrations of the PAH species monitored varied from 3 pg m/sup -3/ to 40 ng m/sup -3/. PAH's with three rings or less were found in significant proportions in the gas phase while larger molecules are almost solely in the particulate phase. Particulate components of the PAH loadings appear to originate locally with Buffalo, NY, Niagara Falls, NY, and Niagara Falls, Ontario, as probably sources. Gas-phase PAH components have a more regional character indicating regional or long-range transport. Levels of benzo(a)pyrene are consistent with previous particulate measurements made along the river since 1981.

  13. Niagara Falls Storage Site annual environmental report for calendar year 1991, Lewiston, New York. [Niagara Falls Storage Site

    SciTech Connect (OSTI)

    Not Available

    1992-09-01

    This document describes the environmental monitoring program at the Niagara Falls Storage Site (NFSS) and surrounding area, implementation of the program, and monitoring results for 1991. Environmental monitoring at NFSS began in 1981. The site is owned by the US Department of Energy (DOE) and is assigned to the DOE Formerly Utilized Sites Remedial Action Program (FUSRAP). FUSRAP is a program to decontaminate or otherwise control sites where residual radioactive materials remain from the early years of the nation's atomic energy program or from commercial operations causing conditions that Congress has authorized DOE to remedy. The environmental monitoring program at NFSS includes sampling networks for radon concentrations in air; external gamma radiation exposure; and total uranium and radium-226 concentrations in surface water, sediments, and groundwater. Additionally, several nonradiological parameters including seven metals are routinely measured in groundwater. Monitoring results are compared with applicable Environmental Protection Agency (EPA) standards, DOE derived concentration guides (DCGs), dose limits, and other requirements in DOE orders. Environmental standards are established to protect public health and the environment.

  14. Niagara Air Quality Survey Report, 1987: Occidental Chemical Corporation, Niagara Falls, New York, USA, non-aqueous phase liquid (NAPL) incineration test. Report no. ARB-166-87-AR/SP

    SciTech Connect (OSTI)

    Bell, R.W.; DeBrou, G.

    1988-01-01

    An ambient air quality survey was conducted in the Niagara Falls area of Ontario from October 8-12, 1987 to provide on-site real-time screening for selected polychlorinated biphenyl congeners and other chlorinated organics at times when the Occidental Chemical Corporation was conducting tests at its liquid hazardous waste incineration facility in Niagara Falls, N.Y. During the incineration tests, the winds were such that the gaseous emissions from the Occidental facility were carried into the U.S. Since the monitoring units were restricted to the Canadian side of the Niagara River, only upwind air quality parameters could be measured.

  15. Evaluation of Final Radiological Conditions at Areas of the Niagara Falls Storage Site Remediated under the Formerly Utilized Sites Remedial Action Program

    Broader source: Energy.gov [DOE]

    Evaluation of Final Radiological Conditions at Areas of the Niagara Falls Storage Site Remediated under the Formerly Utilized Sites Remedial Action Program (March 2012)

  16. Superfund Record of Decision (EPA Region 2): Love Canal (93rd Street School), Niagara County, City of Niagara Falls, NY. (Third remedial action), (amendment), May 1991. Final report

    SciTech Connect (OSTI)

    Not Available

    1991-05-15

    The Love Canal (93rd Street) site is an inactive hazardous waste site located in Niagara Falls, New York. The 19-acre 93rd Street School site, one of several operable units for the Love Canal Superfund site, is the focus of the Record of Decision (ROD). The fill material is reported to contain fly ash and BHC (a pesticide) waste. The ROD amends the 1988 ROD, and addresses final remediation of onsite contaminated soil through excavation and offsite disposal. The primary contaminants of concern affecting the soil are VOCs including toluene and xylenes; other organics including PAHs and pesticides; and metals including arsenic, chromium, and lead.

  17. Niagara Falls Storage Site, environmental monitoring report for 1979 and 1980

    SciTech Connect (OSTI)

    Weidner, R.B.; Boback, M.W.

    1981-10-05

    The Niagara Falls Storage Site is a 190-acre facility located in Niagara County, New York. It is owned by the US Department of Energy (DOE) and is used for the storage of radioactive residues. This site is managed by NLO, Inc., contract operator of the DOE Feed Materials Production Center near Cincinnati, Ohio. During 1979 and 1980, water and air samples were collected at and near the storage site to provide information about radionuclides in the offsite environment. Results show that uranium and radium concentrations in ground and surface water were within DOE Guide values for uncontrolled areas. Radon-222 in air at the site west boundary exceeded the DOE Guide but offsite monitoring in the general area showed radon-222 concentrations well within the Guide.

  18. Installation restoration program. Phase I. Records search. Niagara Falls Air Force Reserve facility, New York

    SciTech Connect (OSTI)

    Not Available

    1983-12-01

    The Department of Defense (DOD) has developed a program to identify and evaluate past hazardous material disposal sites on DOD property, to control the migration of hazardous contaminants, and to control hazards to health or welfare that may result from these past disposal operations. This program is called the Installation Restoration Program (IRP). The IRP has four phases consisting of Phase I, Initial Assessment/Records Search; Phase II, Confirmation and Quantification; Phase III, Technology Base Development; and Phase IV, Operations/Remedial Measures. Niagara Falls AFRF is located in Niagara County, New York, approximately six miles northeast of the City of Niagara Falls and approximately fifteen miles north of Buffalo. The installation is currently comprised of 985 acres with a base population of approximately 2,560. The following areas were determined to have a sufficient potential to create environmental contamination and follow-on investigation is warranted: Bldg. 600 JP-4 Pipeline Leak; POL JP-4 Tank C; Landfill; BX MOGAS Tank Leak; NYANG Hazardous Waste Drum Storage; POL JP-4 Tank A; JP-4 Tank Truck Spill; Bldg. 202 Drum Storage Yard; Fire Training Facility No. 1, 2 and 3; Bldg. 850 Drum Storage Yard; and AFRES Hazardous Waste Drum Storage.

  19. Superfund record of decision amendment (EPA Region 2): Hooker (102nd Street Landfill), Niagara Falls, NY, June 9, 1995

    SciTech Connect (OSTI)

    1995-08-01

    This decision document presents the selected modification to the original remedial action (PB91-921417) for the 102nd Street Landfill Site (the `Site`), located in Niagara Falls, New York. The modification to the selected remedy addresses the river sediments within the shallow embayment of the Niagara River adjacent to the Site. The major components of the modification to the selected remedy include: dredging the Niagara River sediments to the `clean line` with respect to Site-related contamination. These sediments, after dewatering, will NOT be incinerated, but will be consolidated on the landfill. Any NAPL found within these sediments will be extracted, and will be incinerated at an off-site facility.

  20. Jet engine test stand and soil stockpile. 107th fighter-interceptor group Niagara Falls Air Force Reserve Station, New York Air National Guard, Niagara Falls, New York. Final site assessment addendum report, 9-12 February 1993

    SciTech Connect (OSTI)

    Not Available

    1994-03-01

    THis report outlines additional site assessment activities which were conducted at the Jet Engine Test Stand (JETS), Building No. 852 located at the 197th Fighter-Interceptor Group, Niagara Falls Air National Guard Station (NFANGS), Air Force Reserve Facility (AFRF) approximately 6 miles northeast of Niagara Falls, New York (Figure 1.1). The additional site assessment activities were performed in response to requests, dated February 9 and 12, 1993, by the New York State Department of Environmental Conservation (NYSDEC) to further investigate contaminated soil and groundwater conditions at the JETS and at an existing soil stockpile (Appendix A).

  1. GROUND LEVEL INVESTIGATION OF ANOMALOUS RADIATION LEVELS IN NIAGARA FALLS, NEW YORK

    Office of Legacy Management (LM)

    GROUND LEVEL INVESTIGATION OF ANOMALOUS RADIATION LEVELS IN NIAGARA FALLS, NEW YORK W. D. Cottrell, D. J. Christian, and F. F. Haywood ,d ;v ~ !;);;J;$ '9;) -i, - 'L." ; i--j -7,) ;3 i, Work performed by Health and Safety Research Division Oak Ridge National Laboratory Oak Ridge, Tennessee 37630 O&J. 2,7 +, / 7&y' March 1979 \ operated by UNION CARBIDE CORPORATIOII for the DEPARTMENT OF ENERGY as part of the Formerly Utilized Sites- Remedial Action Program

  2. Niagara Falls Storage Site environmental report for calendar year 1989, Lewiston, New York

    SciTech Connect (OSTI)

    Not Available

    1990-05-01

    The environmental monitoring program, which began in 1981, was continued during 1989 at the Niagara Falls Storage Site (NFSS), a United States Department of Energy (DOE) surplus facility located in Niagara County, New York, that is currently used for interim storage of radioactive residues, contaminated soils, and rubble. The monitoring program is being conducted by Bechtel National, Inc. The monitoring program at NFSS measures radon concentrations in air; external gamma radiation levels; and uranium and radium concentrations in surface water, groundwater, and sediment. Additionally, several nonradiological parameters are measured in groundwater. To verify that the site is in compliance with the DOE radiation protection standard and to assess its potential effect on public health, the radiation dose was calculated for a hypothetical maximally exposed individual. Based on the conservative scenario described in this report, this hypothetical individual receives an annual external exposure equivalent to approximately 2 percent of the DOE radiation protection standard of 100 mrem/yr. This exposure is less than a person receives during a one-way flight from New York to Los Angeles (because of the greater amounts of cosmic radiation at higher altitudes). The cumulative dose to the population within an 80-km (50-mi) radius of NFSS that results from radioactive materials present at the site is indistinguishable from the dose that the same population receives from naturally occurring radioactive sources. Results of the 1989 monitoring show that NFSS is in compliance with applicable DOE radiation protection standards. 18 refs., 26 figs., 18 tabs.

  3. Niagara Falls Storage Site annual site environmental monitoring report. Calendar year 1985

    SciTech Connect (OSTI)

    Not Available

    1986-04-01

    During 1985, an environmental monitoring program was continued at the Niagara Falls Storage Site (NFSS), a United States Department of Energy (DOE) surplus facility located in Niagara County, New York, presently used for the interim storage of low-level radioactive residues and contaminated soils and rubble. The monitoring program is being conducted by Bechtel National, Inc. Monitoring results show that the NFSS is in compliance with DOE concentration guides and radiation protection standards. Derived Concentration Guides (DCGs) represent the concentrations of radionuclides in air or water that would limit the radiation dose to 100 mrem/yr. The applicable limits have been revised since the 1984 environmental monitoring report was published. The limits applied in 1984 were based on a radiation protection standard of 500 mrem/yr; the limits applied for the 1985 are based on a standard of 100 mrem/yr. To determine whether the site is in compliance with DOE standards, environmental measurements are expressed as percentages of the applicable DCG, while the calculated doses to the public are expressed as percentages of the applicable radiation protection standard. The monitoring program measured radon gas concentrations in air; uranium and radium concentrations in surface water, groundwater, and sediments; and external gamma dose rates. Environmental samples collected were analyzed to determine compliance with applicable standards. Potential radiation doses to the public were also calculated.

  4. Niagara Falls Storage Site environmental monitoring report, Lewiston, New York, calendar year 1984

    SciTech Connect (OSTI)

    Not Available

    1985-07-01

    During 1984, an environmental monitoring program was continued at the Niagara Falls Storage Site, a United States Department of Energy (DOE) surplus facility located in Niagara County, New York, presently used for the storage of radioactive residues, contaminated soils and rubble. The monitoring program measured radon gas concentrations in air; uranium and radium concentrations in surface water, groundwater, and sediments; and external gamma exposure rates. Environmental samples collected were analyzed to determine compliance with applicable standards. Radiation doses to the public were also calculated. During 1984, annual average radon concentrations at the site boundary and exclusion area locations of the site were below the DOE Concentration Guide (CG) for uncontrolled areas. Annual average uranium and radium-226 concentrations in groundwater and surface water were below the DOE CG for release to uncontrolled areas. Sediment samples generally showed average concentrations of uranium and radium-226 lower than those measured in the past years. External gamma exposure rates were below the DOE Radiation Protection Standards. All radiation doses to the public were within DOE standards.

  5. EIS-0109: Long-Term Management of the Existing Radioactive Wastes and Residues at the Niagara Falls Storage Site

    Broader source: Energy.gov [DOE]

    The U.S. Department of Energy developed this statement to evaluate the environmental impacts of several alternatives for management and control of the radioactive wastes and residues at the Niagara Falls Storage Site, including a no action alternative, an alternative to manage wastes on site, and two off-site management alternatives.

  6. Health assessment for S-Area Landfill/Hooker, Niagara Falls, New York, Region 2. CERCLIS No. NYD000000001. Preliminary report

    SciTech Connect (OSTI)

    Not Available

    1989-06-01

    The S-Area Landfill is a National Priorities List site located in Niagara Falls, New York, that was operated from 1947 to 1975 by the Occidental Chemical Corporation (OCC). From 1947 to 1975, OCC is reported to have disposed of an estimated 19,000 tons of chlorobenzenes and approximately 17,000 tons of hexachlorocyclopentadiene. Other wastes disposed of at the site include organic phosphates, hexachlorobutadiene, trichlorophenols, and chlorinated toluenes. Environmental contamination from the S-Area exists on-site and off-site in soils and ground water. Further off-site contamination potentially exists in the Niagara River. The S-Area presents a potential public health threat to the consumers of the City of Niagara Falls drinking water and an incremental increase in contamination to fish in the Niagara River.

  7. COT"IPREITENS IVE RADIOLOGICAL SURVEY OFF-SITE PROPERTY P NIAGARA FALIS STORAGE SITE

    Office of Legacy Management (LM)

    COT"IPREITENS IVE RADIOLOGICAL SURVEY OFF-SITE PROPERTY P NIAGARA FALIS STORAGE SITE LEWISTON, NEW YORK Prepared for U.S. DePartment of EnergY as part of the Formerly Utilized Sites - Remedial ActLon Program J . D . B e r g e r P r o j e c t S t a f f J. Burden* w.L. Smlth* R.D. Condra T.J. Sowell J.S . Epler* G.M. S tePhens P.Iil. Frame L.B. Taus* W . 0 . H e l t o n C . F . W e a v e r R . C . G o s s l e e B . S . Z a c h a r e k d I I Prepared bY Radiological Slte Assessoent Progran

  8. Results of radiological measurements taken in the Niagara Falls, New York, area (NF002)

    SciTech Connect (OSTI)

    Williams, J.K.; Berven, B.A.

    1986-11-01

    The results of a radiological survey of 100 elevated gamma radiation anomalies in the Niagara Falls, New York, area are presented. These radiation anomalies were identified by a mobile gamma scanning survey during the period October 3-16, 1984, and were recommended for an onsite survey to determine if the elevated levels of radiation may be related to the transportation of radioactive waste material to the Lake Ontario Ordnance Works for storage. In this survey, radiological measurements included outdoor gamma exposure rates at 1 m above the surface; outdoor gamma exposure rates at the surface, range of gamma exposure rates during scan; and uranium, radium, and thorium concentrations in biased surface soil samples. The results show 38 anomalies (35 located along Pletcher Road and 3 associated with other unreleated locations) were found to exceed Formerly Utilized Sites Remedial Action Program (FUSRAP) remedial action guidelines and were recommended for formal characterization surveys. (Since the time of this survey, remedial actions have been conducted on the 38 anomalies identified as exceeding FUSRAP guidelines, and the radioactive material above guidelines has been removed.) The remaining 62 anomalies are associated with asphalt driveways and parking lots, which used a phosphate slag material (previously identified as cyclowollastonite, synthetic CaSiO/sub 3/). This rocky-slag waste material was used for bedding under asphalt surfaces and in general gravel applications. Most of the contaminated soil and rock samples collected at the latter anomalies had approximately equal concentrations of /sup 226/Ra and /sup 238/U and, therefore, are not related to materials connected with the Niagara Falls Storage Site (NFSS), including material that was transported to the NFSS. 13 refs., 7 figs., 14 tabs.

  9. Superfund Record of Decision (EPA Region 2): Forest Glen Subdivision, Niagara Falls, NY. (First remedial action), December 1989

    SciTech Connect (OSTI)

    Not Available

    1989-12-29

    The Forest Glen Subdivision site consists of 21 acres of developed residential properties and undeveloped land in Niagara Fall, Niagara County, New York. Land in the area surrounding the Forest Glen subdivision is used for residential and industrial purposes, including a mobile home park, small shopping mall, and the CECOS Landfill. Chemical companies reportedly disposed of wastes onsite from the early 1950s to the early 1970s. Sampling by EPA's Field Investigation Team revealed the presence of high concentrations of unknown and tentatively identified compounds (TICs) in August 1987, and further soil sampling was conducted to identify the TICs. EPA has executed interim measures to stabilize site conditions including collecting, staging, and securing drums in areas north and east of the subdivision and temporarily covering visibily contaminated soil with concrete. The remedial activity is the first of two planned operable units and addresses resident relocation only. A subsequent operable unit will address the remediation of site contamination once the relocation is complete.

  10. Ocean disposal option for bulk wastes containing naturally occurring radionuclides: an assessment case history. [From Niagara Falls storage site

    SciTech Connect (OSTI)

    Stull, E.A.; Merry-Libby, P.

    1985-01-01

    There are 180,000 m/sup 3/ of slightly contaminated radioactive wastes (36 pCi/g radium-226) currently stored at the US Department of Energy's Niagara Falls Storage Site (NFSS), near Lewiston, New York. These wastes resulted from the cleanup of soils that were contaminated above the guidelines for unrestricted use of property. An alternative to long-term management of these wastes on land is dispersal in the ocean. A scenario for ocean disposal is present

  11. U.S. Natural Gas Imports by Pipeline from Mexico

    Annual Energy Outlook [U.S. Energy Information Administration (EIA)]

    St. Clair, MI International Falls, MN Noyes, MN Warroad, MN Babb, MT Havre, MT Port of Del Bonita, MT Port of Morgan, MT Sweetgrass, MT Whitlash, MT Portal, ND Sherwood, ND Pittsburg, NH Champlain, NY Grand Island, NY Massena, NY Niagara Falls, NY Waddington, NY Sumas, WA Highgate Springs, VT North Troy, VT U.S. Pipeline Total from Mexico Ogilby, CA Otay Mesa, CA Alamo, TX El Paso, TX Galvan Ranch, TX Hidalgo, TX McAllen, TX Penitas, TX LNG Imports from Algeria Cove Point, MD Everett, MA Lake

  12. U.S. Total Imports

    U.S. Energy Information Administration (EIA) Indexed Site

    St. Clair, MI International Falls, MN Noyes, MN Warroad, MN Babb, MT Havre, MT Port of Del Bonita, MT Port of Morgan, MT Sweetgrass, MT Whitlash, MT Portal, ND Sherwood, ND Pittsburg, NH Champlain, NY Grand Island, NY Massena, NY Niagara Falls, NY Waddington, NY Sumas, WA Highgate Springs, VT North Troy, VT U.S. Pipeline Total from Mexico Ogilby, CA Otay Mesa, CA Alamo, TX El Paso, TX Galvan Ranch, TX Hidalgo, TX McAllen, TX Penitas, TX LNG Imports from Algeria Cove Point, MD Everett, MA Lake

  13. Niagara Falls Storage Site environmental surveillance report for calendar year 1993

    SciTech Connect (OSTI)

    Not Available

    1994-06-01

    This report summarizes the results of environmental surveillance activities conducted at the Niagara Falls Storage Site (NFSS) during calendar year 1993. It includes an overview of site operations, the basis for radiological and nonradiological monitoring, a summary of the results, and the estimated dose to the offsite population. Environmental surveillance activities were conducted in accordance with the site environmental monitoring plan, which describes the rationale and design criteria for the surveillance program, the frequency of sampling and analysis, specific sampling and analysis procedures, and quality assurance requirements. NFSS is in compliance with National Emission Standards for Hazardous Air Pollutants (NESHAPs) Subpart H of the Clean Air Act as well as the requirements of the National Pollutant Discharge Elimination System (NPDES) under the Clean Water Act. Located in northwestern New York, the site covers 191 acres. From 1944 to the present, the primary use of NFSS has been storage of radioactive residues that were by-products of uranium production. Most onsite areas of residual radioactivity above regulatory guidelines were remediated during the early 1980s. Additional isolated areas of onsite contamination were remediated in 1989, and the materials were consolidated into the waste containment structure in 1991. Remediation of the site has now been completed.

  14. Life state response to environmental crisis: the case of the Love Canal, Niagara Falls, New York

    SciTech Connect (OSTI)

    Masters, S.K.

    1986-01-01

    This thesis explored the differences between two life stages - young and old - in perceiving and responding to man-made environmental disaster, as well as the support resources utilized to cope with disaster - personal, familial/friendship, and organizational. Because of the characteristics of man-made environmental disaster, and because of the different conditions of life and constructions of reality of older and younger families, it was expected that definitions of the situation would vary by life stage and locus of control - authoritative and personal. The research took place in the Love Canal neighborhood of Niagara Falls, New York. Fifty-eight families were interviewed in the fall of 1978, and thirty-nine of these families were reinterviewed in the spring of 1979. Interviews were tape recorded, transcribed, and coded. The data were presented in contingency tables and interview excerpts. The interview schedules elicited information of perception of impact, responses to impact, and the utilization of support resources. In an authoritative locus of control situation, the major findings were that both older and younger families perceived impact, that older families were slightly less disrupted, that younger families relied on organizational and familial/friendship support resources, and that older families relied on familial/friendship support resources.

  15. Environmental monitoring plan for the Niagara Falls Storage Site and the Interim Waste Containment Facility

    SciTech Connect (OSTI)

    Not Available

    1986-04-01

    As part of the US Department of Energy's (DOE) Surplus Facility Management Program (SFMP), the Niagara Falls Storage Site (NFSS) is undergoing remedial action. Vicinity properties adjacent to and near the site are being cleaned up as part of DOE's Formerly Utilized Sites Remedial Action Program (FUSRAP). These programs are a DOE effort to clean up low-level radioactive waste resulting from the early days of the nation's atomic energy program. Radioactively contaminated waste from these remedial action activities are being stored at the NFSS in an interim waste containment facility (IWCF). When the remedial actions and IWCF are completed in 1986, activities at the site will be limited to waste management. The monitoring program was prepared in accordance with DOE Order 5484.1 and is designed to determine the contribution of radioactivity from the site to the environs and to demonstrate compliance with applicable criteria. Major elements of this program will also supplement other monitoring requirements including the performance monitoring system for the IWCF and the closure/post-closure plan. Emphasis will be directed toward the sampling and analysis of groundwater, surface water, air and sediment for parameters which are known to be present in the material stored at the site. The monitoring program will employ a phased approach whereby the first 5 years of data will be evaluated, and the program will be reviewed and modified as necessary. 17 refs., 10 figs., 3 tabs.

  16. Niagara Falls Storage Site annual environmental report for calendar year 1991, Lewiston, New York

    SciTech Connect (OSTI)

    Not Available

    1992-09-01

    This document describes the environmental monitoring program at the Niagara Falls Storage Site (NFSS) and surrounding area, implementation of the program, and monitoring results for 1991. Environmental monitoring at NFSS began in 1981. The site is owned by the US Department of Energy (DOE) and is assigned to the DOE Formerly Utilized Sites Remedial Action Program (FUSRAP). FUSRAP is a program to decontaminate or otherwise control sites where residual radioactive materials remain from the early years of the nation`s atomic energy program or from commercial operations causing conditions that Congress has authorized DOE to remedy. The environmental monitoring program at NFSS includes sampling networks for radon concentrations in air; external gamma radiation exposure; and total uranium and radium-226 concentrations in surface water, sediments, and groundwater. Additionally, several nonradiological parameters including seven metals are routinely measured in groundwater. Monitoring results are compared with applicable Environmental Protection Agency (EPA) standards, DOE derived concentration guides (DCGs), dose limits, and other requirements in DOE orders. Environmental standards are established to protect public health and the environment.

  17. Geochemical information for sites contaminated with low-level radioactive wastes: I. Niagara Falls Storage Site

    SciTech Connect (OSTI)

    Seeley, F.G.; Kelmers, A.D.

    1984-11-01

    The Niagara Falls Storage Site (NFSS) became radioactively contaminated as a result of wastes that were being stored from operations carried out to recover uranium from pitchblende ore in the 1940s and 1950s. The US Department of Energy (DOE) is considering various remedial action options for the NFSS. This report describes the results of geochemical investigations performed to help provide a quantitative evaluation of the effects of various options. NFSS soil and groundwater samples were characterized; and uranium and radium sorption ratios, as well as apparent concentration limit values, were measured in site soil/groundwater systems by employing batch contact methodology. The results suggest that any uranium which is in solution in the groundwater at the NFSS may be poorly retarded due to the low uranium sorption ratio values and high solubility measured. Further, appreciable concentrations of uranium in groundwater could be attained from soluble wastes. Release of uranium via groundwater migration could be a significant release pathway. Solubilized radium would be expected to be effectively retarded by soil at the NFSS as a result of the very high radium sorption ratios observed. The addition of iron oxyhydroxide to NFSS soils resulted in much higher uranium sorption ratios. Additional field testing of this potential remedial action additive could be desirable. 10 references.

  18. Superfund Record of Decision (EPA Region 2): Hooker Chemical S-Area, Niagara Falls, NY. (First remedial action), September 1990. Final report

    SciTech Connect (OSTI)

    Not Available

    1990-09-21

    The Hooker Chemical S-Area site is a former landfill area located in Niagara Falls, New York. The site lies adjacent to the Niagara River. Approximately 63,000 tons of chemical processing wastes were disposed of at the landfill. Ground water beneath the site also has been contaminated from aqueous phase and non-aqueous phase liquid chemicals. Chemicals have migrated toward the Niagara Falls Drinking Water Treatment Plant (DWTP) which lies to the east of the site, contaminating the Bedrock intake structures. The Record of Decision (ROD) addresses the landfill, a contaminated ground water plume, bedrock contamination, and the DWTP. The primary contaminants of concern affecting the soil, sediment, and ground water are VOCs including PCE; and other organics including chlorinated organics and pesticides. The selected remedial action for the site is included.

  19. Superfund Record of Decision (EPA Region 2): Hooker-102nd Street Landfill, Niagara Falls, NY. (First remedial action), September 1990. Final report

    SciTech Connect (OSTI)

    Not Available

    1990-09-26

    The 22-acre Hooker-102nd Street site is a former industrial landfill in the city of Niagara Falls, Niagara County, New York. The site is adjacent to, and partially within the Niagara River's 100-year floodplain. These studies and the Remedial Investigation (RI) initiated in 1984, identified contamination in ground water, onsite and offsite soil, rivershore sediment, and within a storm sewer. Additionally, the presence of a leachate plume of non-aqueous phase liquids (NAPLs) was discovered emanating from the landfill area. The Record of Decision (ROD) is the final remedy which addresses all of the contaminated media. The primary contaminants of concern affecting the soil, sediment, and ground water are VOCs including benzene, TCE, and toluene; other organics including PCBs and phenols; and metals including arsenic.

  20. DOE/OR/20722-133 POST-REMEDIAL ACTION REPORT FOR THE NIAGARA FALLS STORAGE SITE

    Office of Legacy Management (LM)

    OR/20722-133 POST-REMEDIAL ACTION REPORT FOR THE NIAGARA FALLS STORAGE SITE VICINITY PROPERTIES - 1985 AND 1986 JANUARY 1989 Prepared for UNITED STATES DEPARTMENT OF ENERGY OAK RIDGE OPERATIONS OFFICE Under Contract No. DE-AC05-810R20722 M. E. Kaye and A. M. Feldman Bechtel National, Inc. Oak Ridge, Tennessee Bechtel J o b No. 14501 TABLE OF CONTENTS Abbreviations 1.0 Introduction 2.0 Remedial Action Guidelines 3.0 Remedial Action 4.0 Post-Remedial Action Sampling 5.0 Post-Remedial Action Status

  1. Niagara Falls storage site annual environmental report for calendar year 1990, Lewiston, New York

    SciTech Connect (OSTI)

    Not Available

    1991-08-01

    Environmental monitoring of the US DOE Niagara Falls Storage Site (NFSS) and surrounding area began in 1981. NFSS is part of a DOE program to decontaminate or otherwise control sites where residual radioactive materials remain from the early years of the nation's atomic energy program or from commercial, operations causing conditions the Congress has authorized DOE to remedy. Environmental monitoring systems at NFSS include sampling networks for radon concentrations in air; external gamma radiation exposure; and total uranium and radium-226 concentrations in surface water sediments, and groundwater. Additionally, several nonradiological parameters are routinely measured in groundwater. During 1990, the average ambient air radon concentration (including background) at NFSS ranged from 0.3 to 0.7 pCi/L (0.01 to 0.03 Bq/L); the maximum at any location for any quarter was 1.6 pCi/L (0.06 Bq/L). The average on-site external gamma radiation exposure level was 69 mR/yr; the average at the property line was 68 mR/yr (including background). The average background radiation level in the area was 66 mR/yr. Average annual concentrations of radium-226 and total uranium in surface water ranged from 0.4E-9 to 0.9E-9 {mu}Ci/m1 (0.02 to 0.03 Bq/L) and from 5E-9 to 9E-9 {mu}Ci/m1 (0.2 to 0.3 Bq/L), respectively. Routine analyses of groundwater samples from NFSS included the indicator parameters total organic carbon, total organic halides, pH, and specific conductivity.

  2. Engineering evaluation of alternatives for the disposition of Niagara Falls Storage Site, its residues and wastes

    SciTech Connect (OSTI)

    Not Available

    1984-01-01

    The final disposition scenarios selected by DOE for assessment in this document are consistent with those stated in the Notice of Intent to prepare an Environmental Impact Statement (EIS) for the Niagara Falls Storage Site (NFSS) (DOE, 1983d) and the modifications to the alternatives resulting from the public scoping process. The scenarios are: take no action beyond interim remedial measures other than maintenance and surveillance of the NFSS; retain and manage the NFSS as a long-term waste management facility for the wastes and residues on the site; decontaminate, certify, and release the NFSS for other use, with long-term management of the wastes and residues at other DOE sites; and partially decontaminate the NFSS by removal and transport off site of only the more radioactive residues, and upgrade containment of the remaining wastes and residues on site. The objective of this document is to present to DOE the conceptual engineering, occupational radiation exposure, construction schedule, maintenance and surveillance requirements, and cost information relevant to design and implementation of each of the four scenarios. The specific alternatives within each scenario used as the basis for discussion in this document were evaluated on the bases of engineering considerations, technical feasibility, and regulatory requirements. Selected alternatives determined to be acceptable for each of the four final disposition scenarios for the NFSS were approved by DOE to be assessed and costed in this document. These alternatives are also the subject of the EIS for the NFSS currently being prepared by Argonne National Laboratory (ANL). 40 figures, 38 tables.

  3. U.S. Natural Gas Imports by Pipeline from Canada

    Annual Energy Outlook [U.S. Energy Information Administration (EIA)]

    Barbados Total To Brazil Freeport, TX Sabine Pass, LA Total to Canada Eastport, ID Calais, ME Detroit, MI Marysville, MI Port Huron, MI Crosby, ND Portal, ND Sault St. Marie, MI St. Clair, MI Noyes, MN Warroad, MN Babb, MT Havre, MT Port of Morgan, MT Sherwood, ND Pittsburg, NH Buffalo, NY Grand Island, NY Massena, NY Niagara Falls, NY Waddington, NY Sumas, WA Sweetgrass, MT Total to Chile Sabine Pass, LA Total to China Kenai, AK Sabine Pass, LA Total to Egypt Freeport, TX Total to India

  4. U.S. Total Exports

    U.S. Energy Information Administration (EIA) Indexed Site

    Barbados Total To Brazil Freeport, TX Sabine Pass, LA Total to Canada Eastport, ID Calais, ME Detroit, MI Marysville, MI Port Huron, MI Crosby, ND Portal, ND Sault St. Marie, MI St. Clair, MI Noyes, MN Warroad, MN Babb, MT Havre, MT Port of Morgan, MT Sherwood, ND Pittsburg, NH Buffalo, NY Grand Island, NY Massena, NY Niagara Falls, NY Waddington, NY Sumas, WA Sweetgrass, MT Total to Chile Sabine Pass, LA Total to China Kenai, AK Sabine Pass, LA Total to Egypt Freeport, TX Total to India

  5. Superfund record of decision (EPA Region 2): Love Canal, Niagara Falls, New York, October 1987. Second remedial action

    SciTech Connect (OSTI)

    Not Available

    1987-10-26

    The Love Canal site is located in the southeast corner of the city of Niagara Falls and is approximately one-quarter mile north of the Niagara River. The canal was one of two initial excavations designed to provide inexpensive hydroelectric power for industrial development around the turn of the 20th century. Hooker Chemicals and Plastics Corporation (Hooker), now Occidental Chemical Corporation, disposed of over 21,000 tons of chemical wastes, including dioxin-tainted trichlorophenols, into Love Canal between 1942 and 1953. In the mid to late 1970s, continued periods of high precipitation contributed to water accumulation in the disposal area causing chemically-contaminated leachate to be carried to the surface and into contact with residential-basement foundations. Also, dioxin and other contaminants migrated from Love Canal to the sewers which have outfalls to nearby creeks. The remedial program at Love Canal has been extensive and has occurred in two phases. Approximately 30,400 cu yd - 40,900 cu yd of creek and sewer sediments are contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin, commonly referred to as dioxin.

  6. Niagara Falls Storage Site, Annual site environmental report, Lewiston, New York, Calendar year 1986: Surplus Facilities Management Program (SFMP)

    SciTech Connect (OSTI)

    Not Available

    1987-06-01

    During 1986, the environmental monitoring program was continued at the Niagara Falls Storage Site (NFSS), a US Department of Energy (DOE) surplus facility located in Niagara County, New York, presently used for the interim storage of radioactive residues and contaminated soils and rubble. The monitoring program is being conducted by Bechtel National, Inc. The monitoring program at the NFSS measures radon gas concentrations in air; external gamma radiation levels; and uranium and radium concentrations in surface water, groundwater, and sediment. To verify that the site is in compliance with the DOE radiation protection standard and to assess its potential effect on public health, the radiation dose was calculated for the maximally exposed individual. Based on the conservative scenario described in the report, this individual would receive an annual external exposure approximately equivalent to 6% of the DOE radiation protection standard of 100 mrem/yr. By comparison, the incremental dose received from living in a brick house versus a wooden house is 10 mrem/yr above background. The cumulative dose to the population within an 80-km (50-mi) radius of the NFSS that would result from radioactive materials present at the site would be indistinguishable from the dose that the same population would receive from naturally occurring radioactive sources. Results of the 1986 monitoring show that the NFSS is in compliance with the DOE radiation protection standard. 14 refs., 11 figs., 14 tabs.

  7. U.S. Natural Gas Imports by Pipeline from Mexico

    Gasoline and Diesel Fuel Update (EIA)

    Argentina Sabine Pass, LA Total To Barbados Miami, FL Total To Brazil Freeport, TX Sabine Pass, LA Total to Canada Eastport, ID Calais, ME Detroit, MI Marysville, MI Port Huron, MI Crosby, ND Portal, ND Sault St. Marie, MI St. Clair, MI Noyes, MN Babb, MT Havre, MT Port of Morgan, MT Sherwood, ND Pittsburg, NH Buffalo, NY Grand Island, NY Massena, NY Niagara Falls, NY Waddington, NY Sumas, WA Sweetgrass, MT Total to Chile Sabine Pass, LA Total to China Kenai, AK Sabine Pass, LA Total to Egypt

  8. Niagara falls storage site: Annual site environmental report, Lewiston, New York, Calendar Year 1988: Surplus Facilities Management Program (SFMP)

    SciTech Connect (OSTI)

    Not Available

    1989-04-01

    The monitoring program at the Niagara Falls Storage Site (NFSS) measures radon concentrations in air; external gamma radiation levels; and uranium and radium concentrations in surface water, groundwater, and sediment. To verify that the site is in compliance with the DOE radiation protection standard and to assess its potential effect on public health, the radiation dose was calculated for a hypothetical maximally exposed individual. Based on the conservative scenario described in this report, this hypothetical individual receives an annual external exposure approximately equivalent to 6 percent of the DOE radiation protection standard of 100 mrem/yr. This exposure is less than a person receives during two round-trip flights from New York to Los Angeles (because of the greater amounts of cosmic radiation at higher altitudes). The cumulative dose to the population within an 80-km (50-mi) radius of the NFSS that results from radioactive materials present at the site is indistinguishable from the dose that the same population receives from naturally occurring radioactive sources. Results of the 1988 monitoring show that the NFSS is in compliance with applicable DOE radiation protection standards. 17 refs., 31 figs., 20 tabs.

  9. 1,"Robert Moses Niagara","Hydroelectric","New York Power Authority",2438.8

    U.S. Energy Information Administration (EIA) Indexed Site

    York" ,"Plant","Primary energy source","Operating company","Net summer capacity (MW)" 1,"Robert Moses Niagara","Hydroelectric","New York Power Authority",2438.8 2,"Ravenswood","Natural gas","TC Ravenswood LLC",2216.5 3,"Nine Mile Point Nuclear Station","Nuclear","Nine Mile Point Nuclear Sta LLC",1937 4,"Oswego Harbor

  10. Team OptiMN

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    University of Minnesota Team OptiMN "OptiMN Impact Home" Project Summary Designed to fit on the majority of North Minneapolis infill lots, the OptiMN Impact Home is a collaborative project between the University of Minnesota and Urban Homeworks. The overarching goal was a flexible, high-performance, energy-efficient, and affordable house that can be easily built by Urban Homeworks and purchased by eligible low-income residents of North Minneapolis through the Green Homes North program.

  11. Report on the performance monitoring system for the interim waste containment at the Niagara Falls Storage Site, Lewiston, New York

    SciTech Connect (OSTI)

    Not Available

    1985-10-01

    The Niagara Falls Storage Site (NFSS) is an interim storage site for low-level radioactive waste, established by the US Department of Energy (DOE) at Lewiston, New York. The waste containment structure for encapsulating low-level radioactive waste at the NFSS has been designed to minimize infiltration of rainfall, prevent pollution of groundwater, preclude formation of leachate, and prevent radon emanation. Accurately determining the performance of the main engineered elements of the containment structure will be important in establishing confidence in the ability of the structure to retain the wastes. For this purpose, a waste containment performance monitoring system has been developed to verify that these elements are functioning as intended. The key objective of the performance monitoring system is the early detection of trends that could be indicative of weaknesses developing in the containment structure so that corrective action can be taken before the integrity of the structure is compromised. Consequently, subsurface as well as surface monitoring techniques will be used. After evaluating several types of subsurface instrumentation, it was determined that vibrating wire pressure transducers, in combination with surface monitoring techniques, would satisfactorily monitor the parameters of concern, such as water accumulation inside the containment facility, waste settlement, and shrinkage of the clay cover. Surface monitoring will consist of topographic surveys based on predetermined gridlines, walkover surveys, and aerial photography to detect vegetative stress or other changes not evident at ground level. This report details the objectives of the performance monitoring system, identifies the elements of the containment design whose performance will be monitored, describes the monitoring system recommended, and outlines the costs associated with the monitoring system. 5 refs., 4 figs., 3 tabs.

  12. Targeted Health Assessment for Wastes Contained at the Niagara Falls Storage Site to Guide Planning for Remedial Action Alternatives - 13428

    SciTech Connect (OSTI)

    Busse, John; Keil, Karen; Staten, Jane; Miller, Neil; Barker, Michelle; MacDonell, Margaret; Peterson, John; Chang, Young-Soo; Durham, Lisa

    2013-07-01

    The U.S. Army Corps of Engineers (USACE) is evaluating potential remedial alternatives at the 191-acre Niagara Falls Storage Site (NFSS) in Lewiston, New York, under the Formerly Utilized Sites Remedial Action Program (FUSRAP). The Manhattan Engineer District (MED) and Atomic Energy Commission (AEC) brought radioactive wastes to the site during the 1940's and 1950's, and the U.S. Department of Energy (US DOE) consolidated these wastes into a 10-acre interim waste containment structure (IWCS) in the southwest portion of the site during the 1980's. The USACE is evaluating remedial alternatives for radioactive waste contained within the IWCS at the NFSS under the Feasibility Study phase of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) process. A preliminary evaluation of the IWCS has been conducted to assess potential airborne releases associated with uncovered wastes, particularly during waste excavation, as well as direct exposures to uncovered wastes. Key technical issues for this assessment include: (1) limitations in waste characterization data; (2) representative receptors and exposure routes; (3) estimates of contaminant emissions at an early stage of the evaluation process; (4) consideration of candidate meteorological data and air dispersion modeling approaches; and (5) estimates of health effects from potential exposures to both radionuclides and chemicals that account for recent updates of exposure and toxicity factors. Results of this preliminary health risk assessment indicate if the wastes were uncovered and someone stayed at the IWCS for a number of days to weeks, substantial doses and serious health effects could be incurred. Current controls prevent such exposures, and the controls that would be applied to protect onsite workers during remedial action at the IWCS would also effectively protect the public nearby. This evaluation provides framing context for the upcoming development and detailed evaluation of

  13. Design report for the interim waste containment facility at the Niagara Falls Storage Site. [Surplus Facilities Management Program

    SciTech Connect (OSTI)

    Not Available

    1986-05-01

    Low-level radioactive residues from pitchblende processing and thorium- and radium-contaminated sand, soil, and building rubble are presently stored at the Niagara Falls Storage Site (NFSS) in Lewiston, New York. These residues and wastes derive from past NFSS operations and from similar operations at other sites in the United States conducted during the 1940s by the Manhattan Engineer District (MED) and subsequently by the Atomic Energy Commission (AEC). The US Department of Energy (DOE), successor to MED/AEC, is conducting remedial action at the NFSS under two programs: on-site work under the Surplus Facilities Managemnt Program and off-site cleanup of vicinity properties under the Formerly Utilized Sites Remedial Action Program. On-site remedial action consists of consolidating the residues and wastes within a designated waste containment area and constructing a waste containment facility to prevent contaminant migration. The service life of the system is 25 to 50 years. Near-term remedial action construction activities will not jeopardize or preclude implementation of any other remedial action alternative at a later date. Should DOE decide to extend the service life of the system, the waste containment area would be upgraded to provide a minimum service life of 200 years. This report describes the design for the containment system. Pertinent information on site geology and hydrology and on regional seismicity and meteorology is also provided. Engineering calculations and validated computer modeling studies based on site-specific and conservative parameters confirm the adequacy of the design for its intended purposes of waste containment and environmental protection.

  14. Health assessment for Hooker Chemical (102nd Street Landfill), Niagara Falls, New York, Region 2. CERCLIS No. NYD980506810. Preliminary report

    SciTech Connect (OSTI)

    Not Available

    1989-06-01

    The 102nd Street Landfill is two sites that comprise 22 acres. Occidental Chemical Corporation (OCC) and its predecessor, the Oldbury Electrochemical Company, deposited approximately 23,500 tons of mixed organic solvents, organic and inorganic phosphates, and related chemicals. Included in the site are approximately 300 tons of hexachlorocyclohexane process cake, including lindane. In addition, brine sludge, fly ash, electrochemical cell parts and related equipment in unknown quantities were dumped at the site. On-site contamination of the 102nd Street Landfill includes soils contaminated with non-aqueous phase liquids on both portions of the Landfill. Off-site contamination, based on current studies, results from contaminated ground-water leaching into the Niagara River which causes contamination of the river water, sediments, and aquatic organisms, including fish. The 102nd Street Landfill continues to represent a potential public health threat.

  15. Health assessment for Hyde Park Landfill National Priorities List (NPL) site, Niagara Falls, New York, Region 2. CERCLIS No. NYD000831644. Final report

    SciTech Connect (OSTI)

    Not Available

    1989-02-07

    The Hyde Park Landfill National Priorities List Site was used by Hooker Chemical and Plastic Corporation, now Occidental Chemical Corporation, to dispose of approximately 80,000 tons of waste from 1953 to 1975. Significant amounts of 2,3,7,8-tetrachlorodibenzo-p-dioxin is believed to be in the landfill. Site-related contaminants have been detected in the overburden and bedrock aquifers. Analyses of samples taken from ground water seeps at the Niagara Gorge Face also show site-related contaminants. Leachate from the landfill appears to have entered Bloody Run Creek. Sediment sample analyses from the creek show site-related contaminants. The 1985 U.S. Environmental Protection Agency Enforcement Decision Document outlines remedial activities to be conducted at the site. The site without remediation is of potential public health concern because of the risk to human health resulting from possible exposure to hazardous substances at concentrations that may result in adverse health effects.

  16. MN Office of Energy Security | Open Energy Information

    Open Energy Info (EERE)

    MN Office of Energy Security Jump to: navigation, search Name: MN Office of Energy Security Place: St. Paul, MN Website: www.mnofficeofenergysecurity.c References: MN Office of...

  17. Category:Minneapolis, MN | Open Energy Information

    Open Energy Info (EERE)

    16 total. SVFullServiceRestaurant Minneapolis MN Northern States Power Co (Minnesota) Excel Energy.png SVFullServiceRestauran... 89 KB SVHospital Minneapolis MN Northern States...

  18. Selection of clc, cba, and fcb chlorobenzoate-catabolic genotypes from groundwater and surface waters adjacent to the Hyde Park, Niagara Falls, chemical landfill

    SciTech Connect (OSTI)

    Peel, M.C.; Wyndham, R.C.

    1999-04-01

    The frequency of isolation of three nonhomologous chlorobenzoate catabolic genotypes (clc, cba, and fbc) was determined for 464 isolates from freshwater sediments and groundwater in the vicinity of the Hyde Park industrial landfill site in the Niagara watershed. Samples were collected from both contaminated and noncontaminated sites during spring, summer, and fall and enriched at 4, 22, or 32 C with micromolar to millimolar concentrations of chlorobenzoates and 3-chlorobiphenyl. Hybridization at moderate stringency to restriction-digested genomic DNA with DNA probes revealed the chlorocatechol 1,2-dioxygenase operon (clcABD), the 3-chlorobenzoate 3,4-(4,5)-dioxygenase operon (cbaABC), and the 4-chlorobenzoate dehalogenase (fcbB) gene in isolates enriched from all contaminated sites in the vicinity of the industrial landfill. Nevertheless, the known genes were found in less than 10% of the isolates from the contaminated sites, indicating a high level of genetic diversity in the microbial community. The known genotypes were not enriched from the noncontaminated control sites nearby. The clc, cba, and fcb isolates were distributed across five phenotypically distinct groups based on Biolog carbon source utilization, with the breadth of the host range decreasing in the order clc > cba > fcb. Restriction fragment length polymorphism (RFLP) patterns showed that the cba genes were conserved in all isolates whereas the clc and fcb genes exhibited variation in RFLP patterns.

  19. Performance monitoring report for the Niagara Falls Storage Site Waste Containment Structure, Lewiston, New York: Calendar year 1987 and January--June of 1988

    SciTech Connect (OSTI)

    Blanke, J.A.; Johnson, R.T.; Stanley, W.F.

    1989-01-01

    A performance monitoring program has been developed for the Niagara Falls Storage Site (NFSS) Waste Containment Structure (WCS). The WCS contains soils contaminated with residual radioactive materials, rubble, and radioactive residues removed from various areas of the NFSS and vicinity properties during remedial action conducted by the Department of Energy (DOE) from 1982 through 1986. The NFSS is a part of the DOE Surplus Facilities Management Program (SFMP). The purpose of the performance monitoring program is to verify that the WCS main engineering elements are functioning to minimize infiltration of rainfall; prevent pollution of groundwater; preclude formation of leachate; and prevent radon emanation. This report presents the findings of performance monitoring conducted at the WCS during calendar year 1987, and January through June of 1988. the data received during the initial performance monitoring period in 1986 (Ref. 3) established a baseline for interpretation contained in this report. The period covered by this report has been expanded to include 6 months in 1988 because the impact of the winter is most evident in the spring growing season. 5 refs., 12 figs., 8 tabs.

  20. Niagara Falls Storage Site environmental report for calendar year 1992, 1397 Pletcher Road, Lewiston, New York. Formerly Utilized Sites Remedial Action Program (FUSRAP)

    SciTech Connect (OSTI)

    Not Available

    1993-05-01

    This report describes the environmental surveillance program at the Niagara Falls Storage Site (NFSS) and provides the results for 1992. From 1944 to the present, the primary use of NFSS has been storage of radioactive residues produced as a by-product of uranium production. All onsite areas of residual radioactivity above guidelines have been remediated. Materials generated during remediation are stored onsite in the 4-ha (10-acre) waste containment structure (WCS). The WCS is a clay-lined, clay-capped, and grass-covered storage pile. The environmental surveillance program at NFSS includes sampling networks for radon concentrations in air; external gamma radiation exposure; and total uranium and radium-226 concentrations in surface water, sediments, and groundwater. Several chemical parameters, including seven metals, are also routinely measured in groundwater. This surveillance program assists in fulfilling the DOE policy of measuring and monitoring effluents from DOE activities and calculating hypothetical doses. Monitoring results are compared with applicable Environmental Protection Agency (EPA) and New York State Department of Environmental Conservation (NYSDEC) standards, DOE derived concentration guides (DCGs), dose limits, and other DOE requirements. Results of environmental monitoring during 1992 indicate that levels of the parameters measured were in compliance with all but one requirement: Concentrations of iron and manganese in groundwater were above NYSDEC groundwater quality standards. However, these elements occur naturally in the soils and groundwater associated with this region. In 1992 there were no environmental occurrences or reportable quantity releases.

  1. Niagara Falls Storage Site, Lewiston, New York: Annual site environmental report, Calendar year 1987: Formerly Utilized Sites Remedial Action Program (FUSRAP)

    SciTech Connect (OSTI)

    Not Available

    1988-04-01

    The monitoring program at the Niagara Falls Storage Site (NFSS) measures radon gas concentrations in air; external gamma radiation levels; and uranium and radium concentrations in surface water, groundwater, and sediment. To verify that the site is in compliance with the DOE radiation protection standard and to assess its potential effect on public health, the radiation dose was calculated for the maximally exposed individual. Based on the conservative scenario described in the report, this individual would receive an annual external exposure approximately equivalent to 6 percent of the DOE radiation protection standard of 100 mrem/yr. By comparison, the incremental dose received from living in a brick house versus a wooden house is 10 mrem/yr above background. The cumulative dose to the population within an 80-km (50-mi) radius of the NFSS that would result from radioactive materials present at the site would be indistinguishable from the dose that the same population would receive from naturally occurring radioactive sources. Results of the 1987 monitoring show that the NFSS is in compliance with the DOE radiation protection standard. 13 refs., 10 figs., 20 tabs.

  2. Assessment of alternatives for long-term management of uranium ore residues and contaminated soils located at DOE's Niagara Falls Storage Site

    SciTech Connect (OSTI)

    Merry-Libby, P.

    1984-11-05

    About 11,000 m/sup 3/ of uranium ore residues and 180,000 m/sup 3/ of wastes (mostly slightly contaminated soils) are consolidated within a diked containment area at the Niagara Falls Storage Site (NFSS) located about 30 km north of Buffalo, NY. The residues account for less than 6% of the total volume of contaminated materials but almost 99% of the radioactivty. The average /sup 226/Ra concentration in the residues is 67,000 pCi/g. Several alternatives for long-term management of the wastes and residues are being considered, including: improvement of the containment at NFSS, modification of the form of the residues, management of the residues separately from the wastes, management of the wastes and residues at another humid site (Oak Ridge, TN) or arid site (Hanford, WA), and dispersal of the wastes in the ocean. Potential radiological risks are expected to be smaller than the nonradiological risks of occupational and transportation-related injuries and deaths. Dispersal of the slightly contaminated wastes in the ocean is not expected to result in any significant impacts on the ocean environment or pose any significant radiological risk to humans. It will be necessary to take perpetual care of the near-surface burial sites because the residues and wastes will remain hazardous for thousands of years. If controls cease, the radioactive materials will eventually be dispersed in the environment. Predicted loss of the earthen covers over the buried materials ranges from several hundred to more than two million years, depending primarily on the use of the land surface. Groundwater will eventually be contaminated in all alternatives; however, the groundwater pathway is relatively insignificant with respect to radiological risks to the general population. A person intruding into the residues would incur an extremely high radiation dose.

  3. Evaluation of Final Radiological Conditions at Areas of the Niagara Falls Storage Site Remediated under the Formerly Utilized Sites Remedial Action Program -12184

    SciTech Connect (OSTI)

    Clayton, Christopher; Kothari, Vijendra; Starr, Ken; Widdop, Michael; Gillespie, Joey

    2012-02-26

    The U. S. Department of Energy (DOE) methods and protocols allow evaluation of remediation and final site conditions to determine if remediated sites remain protective. Two case studies are presented that involve the Niagara Falls Storage Site (NFSS) and associated vicinity properties (VPs), which are being remediated under the Formerly Utilized Sites Remedial Action Program (FUSRAP). These properties are a part of the former Lake Ontario Ordnance Works (LOOW). In response to stakeholders concerns about whether certain remediated NFSS VPs were putting them at risk, DOE met with stakeholders and agreed to evaluate protectiveness. Documentation in the DOE records collection adequately described assessed and final radiological conditions at the completed VPs. All FUSRAP wastes at the completed sites were cleaned up to meet DOE guidelines for unrestricted use. DOE compiled the results of the investigation in a report that was released for public comment. In conducting the review of site conditions, DOE found that stakeholders were also concerned about waste from the Separations Process Research Unit (SPRU) at the Knolls Atomic Power Laboratory (KAPL) that was handled at LOOW. DOE agreed to determine if SPRU waste remained at that needed to be remediated. DOE reviewed records of waste characterization, historical handling locations and methods, and assessment and remediation data. DOE concluded that the SPRU waste was remediated on the LOOW to levels that pose no unacceptable risk and allow unrestricted use and unlimited exposure. This work confirms the following points as tenets of an effective long-term surveillance and maintenance (LTS&M) program:  Stakeholder interaction must be open and transparent, and DOE must respond promptly to stakeholder concerns.  DOE, as the long-term custodian, must collect and preserve site records in order to demonstrate that remediated sites pose no unacceptable risk.  DOE must continue to maintain constructive relationships

  4. Mn4+ emission in pyrochlore oxides

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Du, Mao-Hua

    2015-01-01

    For the existing Mn4+ activated red phosphors have relatively low emission energies (or long emission wavelengths) and are therefore inefficient for general lighting. Density functional calculations are performed to study Mn4+ emission in rare-earth hafnate, zirconate, and stannate pyrochlore oxides (RE2Hf2O7, RE2Zr2O7, and RE2Sn2O7). We show how the different sizes of the RE3+ cation in these pyrochlores affect the local structure of the distorted MnO6 octahedron, the Mn–O hybridization, and the Mn4+ emission energy. The Mn4+ emission energies of many pyrochlores are found to be higher than those currently known for Mn4+ doped oxides and should be closer to thatmore » of Y2O3:Eu3+ (the current commercial red phosphor for fluorescent lighting). The O–Mn–O bond angle distortion in a MnO6 octahedron is shown to play an important role in weakening Mn–O hybridization and consequently increasing the Mn4+ emission energy. Our result shows that searching for materials that allow significant O–Mn–O bond angle distortion in a MnO6 octahedron is an effective approach to find new Mn4+ activated red phosphors with potential to replace the relatively expensive Y2O3:Eu3+ phosphor.« less

  5. CRAD, NNSA - Maintenance (MN) | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    NNSA - Maintenance (MN) CRAD, NNSA - Maintenance (MN) CRAD for Maintenance (MN). Criteria Review and Approach Documents (CRADs) that can be used to conduct a well-organized and thorough assessment of elements of safety and health programs. CRADs consist of a Performance Objective that identifies the expectation(s) or requirement(s) to be verified, which reflect the complete scope of the assessment; Criteria that provide specifics by which the performance objectives are measured, including

  6. DOE - Office of Legacy Management -- Elk River Reactor - MN 01

    Office of Legacy Management (LM)

    Elk River Reactor - MN 01 FUSRAP Considered Sites Site: Elk River Reactor (MN.01 ) Eliminated from consideration under FUSRAP - Reactor was dismantled and decommissioned by 1974 Designated Name: Not Designated Alternate Name: None Location: Elk River , Minnesota MN.01-1 Evaluation Year: 1985 MN.01-1 Site Operations: Boiling water reactor demonstration, research and development program MN.01-1 Site Disposition: Eliminated MN.01-1 Radioactive Materials Handled: None Indicated Primary Radioactive

  7. Magnetostructural phase transformations in Tb 1-x Mn 2 (Journal...

    Office of Scientific and Technical Information (OSTI)

    phase transformations in Tb 1-x Mn 2 Citation Details In-Document Search Title: Magnetostructural phase transformations in Tb 1-x Mn 2 Magnetism and phase transformations ...

  8. Magnetocrystalline anisotropy in UMn<mn>2mn>Ge>2mn> and related Mn-based actinide ferromagnets

    SciTech Connect (OSTI)

    Parker, David S.; Ghimire, Nirmal; Singleton, John; Thompson, J. D.; Bauer, Eric D.; Baumbach, Ryan; Mandrus, David; Li, Ling; Singh, David J.

    2015-05-04

    We present magnetization isotherms in pulsed magnetic fields up to 62 Tesla, supported by first principles calculations, demonstrating a huge uniaxial magnetocrystalline anisotropy energy - approximately 20 MJ/m3 - in UMn<mn>2mn>Ge>2mn>. This large anisotropy results from the extremely strong spin-orbit coupling affecting the uranium 5 f electrons, which in the calculations exhibit a substantial orbital moment exceeding 2 μB. Finally, we also find from theoretical calculations that a number of isostructural Mn-actinide compounds are expected to have similarly large anisotropy.

  9. Evaluation of Final Radiological Conditions at Areas of the Niagara Falls Storage Site Remediated under the Formerly Utilized Sites Remedial Action Program - 12184

    SciTech Connect (OSTI)

    Clayton, Christopher; Kothari, Vijendra; Starr, Ken; Widdop, Michael; Gillespie, Joey

    2012-07-01

    The U.S. Department of Energy (DOE) methods and protocols allow evaluation of remediation and final site conditions to determine if remediated sites remain protective. Two case studies are presented that involve the Niagara Falls Storage Site (NFSS) and associated vicinity properties (VPs), which are being remediated under the Formerly Utilized Sites Remedial Action Program (FUSRAP). These properties are a part of the former Lake Ontario Ordnance Works (LOOW). In response to stakeholders concerns about whether certain remediated NFSS VPs were putting them at risk, DOE met with stakeholders and agreed to evaluate protectiveness. Documentation in the DOE records collection adequately described assessed and final radiological conditions at the completed VPs. All FUSRAP wastes at the completed sites were cleaned up to meet DOE guidelines for unrestricted use. DOE compiled the results of the investigation in a report that was released for public comment. In conducting the review of site conditions, DOE found that stakeholders were also concerned about waste from the Separations Process Research Unit (SPRU) at the Knolls Atomic Power Laboratory (KAPL) that was handled at LOOW. DOE agreed to determine if SPRU waste remained at that needed to be remediated. DOE reviewed records of waste characterization, historical handling locations and methods, and assessment and remediation data. DOE concluded that the SPRU waste was remediated on the LOOW to levels that pose no unacceptable risk and allow unrestricted use and unlimited exposure. This work confirms the following points as tenets of an effective long-term surveillance and maintenance (LTS and M) program: - Stakeholder interaction must be open and transparent, and DOE must respond promptly to stakeholder concerns. - DOE, as the long-term custodian, must collect and preserve site records in order to demonstrate that remediated sites pose no unacceptable risk. - DOE must continue to maintain constructive relationships with

  10. Magnetic coupling in ferromagnetic semiconductor (Ga,Mn)As/(Al,Ga,Mn)As bilayers

    SciTech Connect (OSTI)

    Wang, M.; Wadley, P.; Campion, R. P.; Rushforth, A. W.; Edmonds, K. W.; Gallagher, B. L.; Charlton, T. R.; Kinane, C. J.; Langridge, S.

    2015-08-07

    We report on a study of ferromagnetic semiconductor (Ga,Mn)As/(Al,Ga,Mn)As bilayers using magnetometry and polarized neutron reflectivity (PNR). From depth-resolved characterization of the magnetic structure obtained by PNR, we concluded that the (Ga,Mn)As and (Al,Ga,Mn)As layers have in-plane and perpendicular-to-plane magnetic easy axes, respectively, with weak interlayer coupling. Therefore, the layer magnetizations align perpendicular to each other under low magnetic fields and parallel at high fields.

  11. SSL Demonstration: Bridge Lighting, Minneapolis, MN

    SciTech Connect (OSTI)

    2014-10-01

    DOE Solid-State Lighting GATEWAY summary brief for Phase II report on the longer-term performance of LED lighting installed in 2008 on the I-35W Bridge in Minneapolis, MN.

  12. High Mn austenitic stainless steel

    DOE Patents [OSTI]

    Yamamoto, Yukinori [Oak Ridge, TN; Santella, Michael L [Knoxville, TN; Brady, Michael P [Oak Ridge, TN; Maziasz, Philip J [Oak Ridge, TN; Liu, Chain-tsuan [Knoxville, TN

    2010-07-13

    An austenitic stainless steel alloy includes, in weight percent: >4 to 15 Mn; 8 to 15 Ni; 14 to 16 Cr; 2.4 to 3 Al; 0.4 to 1 total of at least one of Nb and Ta; 0.05 to 0.2 C; 0.01 to 0.02 B; no more than 0.3 of combined Ti+V; up to 3 Mo; up to 3 Co; up to 1W; up to 3 Cu; up to 1 Si; up to 0.05 P; up to 1 total of at least one of Y, La, Ce, Hf, and Zr; less than 0.05 N; and base Fe, wherein the weight percent Fe is greater than the weight percent Ni, and wherein the alloy forms an external continuous scale including alumina, nanometer scale sized particles distributed throughout the microstructure, the particles including at least one of NbC and TaC, and a stable essentially single phase FCC austenitic matrix microstructure that is essentially delta-ferrite-free and essentially BCC-phase-free.

  13. Local environment of Mn in Mn delta-doped Si layers

    SciTech Connect (OSTI)

    Xiao, Q.F.; Kahwaji, S.; Monchesky, T.L.; Gordon, R.A.; Crozier, E.D.

    2009-11-09

    Dilute magnetic semiconductors combine both magnetic ordering and semiconducting behaviour, leading to potential spintronic applications. Silicon containing dilute Mn impurities is a potential dilute magnetic semiconductor. We have grown Mn delta-doped films by deposition of 0.7 of a monolayer of Mn on Si(001) by molecular beam epitaxy and capping the film with Si. The magnetic properties are likely sensitive to the distribution of Mn on substitutional or interstitial sites and the formation of metallic precipitates. We have used polarization-dependent XAFS to examine the local structure. We compare to a thicker MnSi film grown on Si(111) and also examine the influence of lead on the manganese environment when used as a surfactant in the growth process.

  14. Structural, magnetic, and superconducting properties of pulsed-laser-deposition-grown La<mn>1.85mn> Sr<mn>0.15mn> CuO<mn>4mn> / La<mn>2mn>/>3mn> Ca<mn>1mn>/>3mn> MnO>3mn> superlattices on (001)-oriented LaSrAlO<mn>4mn> substrates

    SciTech Connect (OSTI)

    Das, S.; Sen, K.; Marozau, I.; Uribe-Laverde, M. A.; Biskup, N.; Varela, M.; Khaydukov, Y.; Soltwedel, O.; Keller, T.; Döbeli, M.; Schneider, C. W.; Bernhard, C.

    2014-03-12

    Epitaxial La<mn>1.85mn> Sr<mn>0.15mn> CuO<mn>4mn> / La<mn>2mn>/>3mn> Ca<mn>1mn>/>3mn> MnO>3mn> (LSCO/LCMO) superlattices (SL) on (001)- oriented LaSrAlO4 substrates have been grown with pulsed laser deposition (PLD) technique. Their structural, magnetic and superconducting properties have been determined with in-situ reflection high energy electron diffraction (RHEED), x-ray diffraction, specular neutron reflectometry, scanning transmission electron microscopy (STEM), electric transport, and magnetization measurements. We find that despite the large mismatch between the in-plane lattice parameters of LSCO (a = 0.3779 nm) and LCMO (a = 0.387 nm) these superlattices can be grown epitaxially and with a high crystalline quality. While the first LSCO layer remains clamped to the LSAO substrate, a sizeable strain relaxation occurs already in the first LCMO layer. The following LSCO and LCMO layers adopt a nearly balanced state in which the tensile and compressive strain effects yield alternating in-plane lattice parameters with an almost constant average value. No major defects are observed in the LSCO layers, while a significant number of vertical antiphase boundaries are found in the LCMO layers. The LSCO layers remain superconducting with a relatively high superconducting onset temperature of Tconset ≈ 36 K. The macroscopic superconducting response is also evident in the magnetization data due to a weak diamagnetic signal below 10 K for H ∥ ab and a sizeable paramagnetic shift for H ∥ c that can be explained in terms of a vortex-pinning-induced flux compression. The LCMO layers maintain a

  15. Properties of (Ga,Mn)As codoped with Li

    SciTech Connect (OSTI)

    Miyakozawa, Shohei; Chen, Lin; Matsukura, Fumihiro; Ohno, Hideo

    2014-06-02

    We grow Li codoped (Ga,Mn)As layers with nominal Mn composition up to 0.15 by molecular beam epitaxy. The layers before and after annealing are characterized by x-ray diffraction, transport, magnetization, and ferromagnetic resonance measurements. The codoping with Li reduces the lattice constant and electrical resistivity of (Ga,Mn)As after annealing. We find that (Ga,Mn)As:Li takes similar Curie temperature to that of (Ga,Mn)As, but with pronounced magnetic moments and in-plane magnetic anisotropy, indicating that the Li codoping has nontrivial effects on the magnetic properties of (Ga,Mn)As.

  16. Spin reorientation and Ce-Mn coupling in antiferromagnetic oxypnictide CeMnAsO

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Qiang; Tian, Wei; Peterson, Spencer G.; Dennis, Kevin W.; Vaknin, David

    2015-02-18

    Structure and magnetic properties of high-quality polycrystlline CeMnAsO, a parent compound of the “1111”-type oxypnictides, have been investigated using neutron powder diffraction and magnetization measurements. We find that CeMnAsO undergoes a C-type antiferromagnetic order with Mn2+(S = 5/2) moments pointing along the c axis below a relatively high Néel temperature of TN = 347(1) K. Below TSR = 35 K, two simultaneous transitions occur where the Mn moments reorient from the c axis to the ab plane preserving the C-type magnetic order, and Ce moments undergo long-range AFM ordering with antiparallel moments pointing in the ab plane. Another transition tomore » a noncollinear magnetic structure occurs below 7 K. The ordered moments of Mn and Ce at 2 K are 3.32(4) μB and 0.81(4)μB, respectively. We find that CeMnAsO primarily falls into the category of a local-moment antiferromagnetic insulator in which the nearest-neighbor interaction (J1) is dominant with J2 < J1/2 in the context of J1 – J2 – Jc model. The spin reorientation transition driven by the coupling between Ce and the transition metal seems to be common to Mn, Fe, and Cr ions, but not to Co and Ni ions in the isostructural oxypnictides. As a result, a schematic illustration of magnetic structures in Mn and Ce sublattices in CeMnAsO is presented.« less

  17. Magnetoelectric coupling tuned by competing anisotropies in Mn...

    Office of Scientific and Technical Information (OSTI)

    Magnetoelectric coupling tuned by competing anisotropies in Mn 1 - x Ni x TiO 3 Prev Next Title: Magnetoelectric coupling tuned by competing anisotropies in Mn 1 - x Ni x TiO ...

  18. Influence of interstitial Mn on magnetism in room-temperature ferromagnet Mn(1+delta)Sb

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Taylor, Alice E; Berlijn, Tom; Hahn, Steven E; May, Andrew F; Williams, Travis J; Poudel, Lekhanath N; Calder, Stuart A; Fishman, Randy Scott; Stone, Matthew B; Aczel, Adam A; et al

    2015-01-01

    We report elastic and inelastic neutron scattering measurements of the high-TC ferromagnet Mn(1+delta)Sb. Measurements were performed on a large, TC = 434 K, single crystal with interstitial Mn content of delta=0.13. The neutron diffraction results reveal that the interstitial Mn has a magnetic moment, and that it is aligned antiparallel to the main Mn moment. We perform density functional theory calculations including the interstitial Mn, and find the interstitial to be magnetic in agreement with the diffraction data. The inelastic neutron scattering measurements reveal two features in the magnetic dynamics: i) a spin-wave-like dispersion emanating from ferromagnetic Bragg positions (Hmore » K 2n), and ii) a broad, non-dispersive signal centered at forbidden Bragg positions (H K 2n+1). The inelastic spectrum cannot be modeled by simple linear spin-wave theory calculations, and appears to be significantly altered by the presence of the interstitial Mn ions. The results show that the influence of the int« less

  19. CaMn2Al10: Itinerant Mn magnetism on the verge of magnetic order

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Steinke, L.; Simonson, J. W.; Yin, W. -G.; Smith, G. J.; Kistner-Morris, J. J.; Zellman, S.; Puri, A.; Aronson, M. C.

    2015-07-24

    We report the discovery of CaMn2Al10, a metal with strong magnetic anisotropy and moderate electronic correlations. Magnetization measurements find a Curie-Weiss moment of 0.83μB/Mn, significantly reduced from the Hund's rule value, and the magnetic entropy obtained from specific heat measurements is correspondingly small, only ≈ 9% of Rln2. These results imply that the Mn magnetism is highly itinerant, a conclusion supported by density functional theory calculations that find strong Mn-Al hybridization. Consistent with the layered nature of the crystal structure, the magnetic susceptibility χ is anisotropic below 20 K, with a maximum ratio of χ[010]/χ[001] ≈ 3.5. A strong power-lawmore » divergence χ(T) ~ T–1.2 below 20 K implies incipient ferromagnetic order, an Arrott plot analysis of the magnetization suggests a vanishing low Curie temperature TC ~ 0. Our experiments indicate that CaMn2Al10 is a rare example of a system where the weak and itinerant Mn-based magnetism is poised on the verge of order.« less

  20. Influence of interstitial Mn on magnetism in room-temperature ferromagnet Mn(1+delta)Sb

    SciTech Connect (OSTI)

    Taylor, Alice E; Berlijn, Tom; Hahn, Steven E; May, Andrew F; Williams, Travis J; Poudel, Lekhanath N; Calder, Stuart A; Fishman, Randy Scott; Stone, Matthew B; Aczel, Adam A; Cao, Huibo; Lumsden, Mark D; Christianson, Andrew D

    2015-01-01

    We report elastic and inelastic neutron scattering measurements of the high-TC ferromagnet Mn(1+delta)Sb. Measurements were performed on a large, TC = 434 K, single crystal with interstitial Mn content of delta=0.13. The neutron diffraction results reveal that the interstitial Mn has a magnetic moment, and that it is aligned antiparallel to the main Mn moment. We perform density functional theory calculations including the interstitial Mn, and find the interstitial to be magnetic in agreement with the diffraction data. The inelastic neutron scattering measurements reveal two features in the magnetic dynamics: i) a spin-wave-like dispersion emanating from ferromagnetic Bragg positions (H K 2n), and ii) a broad, non-dispersive signal centered at forbidden Bragg positions (H K 2n+1). The inelastic spectrum cannot be modeled by simple linear spin-wave theory calculations, and appears to be significantly altered by the presence of the interstitial Mn ions. The results show that the influence of the int

  1. Opti-MN Impact House Presentation | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Opti-MN Impact House Presentation Opti-MN Impact House Presentation Opti-MN was the Grand Winner of the 2015 Race to Zero Student Design Competition. View the presentation for the Opti-MN Impact House below. Read a full list of the winning teams. Opti-MN Presentation (5.74 MB) More Documents & Publications 2015 Race to Zero Competition Grand Winner and Grand Winner Finalist Team Submissions 2016 Race to Zero Competition Winner Team Presentations 2014 Race to Zero Student Design Competition:

  2. Unexpected crystal and magnetic structures in MnCu4In and MnCu4Sn

    SciTech Connect (OSTI)

    Provino, A.; Paudyal, D.; Fornasini, ML; Dhiman, I.; Dhar, SK.; Das, A.; Mudryk, Y.; Manfrinetti, P.; Pecharsky, VK

    2013-01-29

    We discovered a new compound MnCu4In with its own hexagonal structure type (hP12-P63mc, ternary ordered derivative of the hexagonal MgZn2-type) that becomes ferromagnetic at TC = 540 K. This transition temperature is higher than that found in the MnCu2In and MnCu2Sn alloys. In contrast, the homologous compound MnCu4Sn, which crystallizes in the cubic MgCu4Sn-type, orders antiferromagnetically with TN = 110 K. The neutron diffraction studies show ferromagnetic spin orientation in the {1 0 1} plane in MnCu4In with a magnetic moment of 4.5 ?B/Mn at 22 K, and a corresponding value of 4.7 ?B/Mn in the antiferromagnetic MnCu4Sn with propagation vector View the MathML source. The first-principles electronic structure calculations show that the unexpected difference in both magnetic and crystal structures of MnCu4In and MnCu4Sn is due to the difference in the Mn-3d bands and exchange interactions relating to different crystal anisotropy, coordination numbers, and interatomic distances.

  3. Solid Solution Phases in the Olivine-Type LiMnPO4/MnPO4 System

    SciTech Connect (OSTI)

    Chen, Guoying; Richardson, Thomas J.

    2009-04-07

    Nonstoichiometry is reported in the LiMnPO{sub 4}/MnPO{sub 4} system for the first time. As lithium is removed from crystalline LiMnPO{sub 4} by chemical or electrochemical methods, the resulting two phase mixture consists of stoichiometric LiMnPO{sub 4} and a delithiated phase, Li{sub y}MnPO{sub 4}, whose lattice parameters depend upon the global extent of delithiation and on the crystalline domain size of the delithiated phase. This behavior is reproduced during electrochemical insertion of lithium. Again, no evidence for nonstoichiometry was found in the vicinity of LiMnPO{sub 4}. Attempts to create single phase solid solutions by heating mixtures of the two phases failed due to the thermal instability of Li{sub y}MnPO{sub 4}.

  4. Investigations of element spatial correlation in Mn-promoted...

    Office of Scientific and Technical Information (OSTI)

    Investigations of element spatial correlation in Mn-promoted Co-based Fischer-Tropsch synthesis catalysts This content will become publicly available on June 4, 2017 Title: ...

  5. Microsoft Word - MnO_Reduction bh

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    May 2016 Figure 1. Schematic of flow-through system developed at SSRL. A reaction vessel with manganese oxides and media required for microbial experiments was kept anoxic with nitrogen gas and pH was measured using an environmental pH probe. A portion of the fluid was sampled using a peristaltic pump through anaerobic tubing to the beam line hutch where the x-ray beam sampled the Mn coordination environment, mineralogy, and redox state through a Kapton tape window on an x-ray flow-through cell.

  6. Spin caloritronics in graphene with Mn

    SciTech Connect (OSTI)

    Torres, Alberto Lima, Matheus P. Fazzio, A.; Silva, Antnio J. R. da

    2014-02-17

    We show that graphene with Mn adatoms trapped at single vacancies features spin-dependent Seebeck effect, thus enabling the use of this material for spin caloritronics. A gate potential can be used to tune its thermoelectric properties in a way it presents either a total spin polarized current, flowing in one given direction, or currents for both spins flowing in opposite directions without net charge transport. Moreover, we show that the thermal magnetoresistance can be tuned between ?100% and +100% by varying a gate potential.

  7. Magnetic Moment Enhancement for Mn7 Cluster on Graphene

    SciTech Connect (OSTI)

    Liu, Xiaojie; Wang, Cai-Zhuang; Lin, Hai-Qing; Ho, Kai-Ming

    2014-08-21

    Mn7 cluster on graphene with different structural motifs and magnetic orders are investigated systematically by first-principles calculations. The calculations show that Mn7 on graphene prefers a two-layer motif and exhibits a ferrimagnetic coupling. The magnetic moment of the Mn7 cluster increases from 5.0 ?B at its free-standing state to about 6.0 ?B upon adsorption on graphene. Mn7 cluster also induces about 0.3 ?B of magnetic moment in the graphene layer, leading to an overall enhancement of 1.3 ?B magnetic moment for Mn7 on graphene. Detail electron transfer and bonding analysis have been carried out to investigate the origin of the magnetic enhancement.

  8. Mn4+ emission in pyrochlore oxides

    SciTech Connect (OSTI)

    Du, Mao-Hua

    2015-01-01

    For the existing Mn4+ activated red phosphors have relatively low emission energies (or long emission wavelengths) and are therefore inefficient for general lighting. Density functional calculations are performed to study Mn4+ emission in rare-earth hafnate, zirconate, and stannate pyrochlore oxides (RE2Hf2O7, RE2Zr2O7, and RE2Sn2O7). We show how the different sizes of the RE3+ cation in these pyrochlores affect the local structure of the distorted MnO6 octahedron, the Mn–O hybridization, and the Mn4+ emission energy. The Mn4+ emission energies of many pyrochlores are found to be higher than those currently known for Mn4+ doped oxides and should be closer to that of Y2O3:Eu3+ (the current commercial red phosphor for fluorescent lighting). The O–Mn–O bond angle distortion in a MnO6 octahedron is shown to play an important role in weakening Mn–O hybridization and consequently increasing the Mn4+ emission energy. Our result shows that searching for materials that allow significant O–Mn–O bond angle distortion in a MnO6 octahedron is an effective approach to find new Mn4+ activated red phosphors with potential to replace the relatively expensive Y2O3:Eu3+ phosphor.

  9. Electrochemical behavior of β-MnO{sub 2} and MnOOH nanorods in different electrolytes

    SciTech Connect (OSTI)

    Chinnasamy, Revathi; Thangavelu, Rajendrakumar Ramasamy

    2015-06-24

    A manganese dioxide (β-MnO{sub 2}) and MnOOH nanoparticles has been synthesized by hydrothermal method. As prepared samples are analyzed by X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). FESEM showed rod morphology within the diameter of 50–200 and length of few nanometers. These nanorods are immobilized on a Glassy Carbon Electrode (GCE) by drop cast method. The comparative electrochemical behavior of β-MnO{sub 2} and MnOOH rod modified GCE electrodes are analyzed by cyclic Voltammetry (CV) method in different electrolytes of 0.1M KCl, 0.1M Na{sub 2}SO{sub 4}, 0.1M NaOH, 0.1M PBS, 0.1M H{sub 2}SO{sub 4}. From the cyclic Voltammetry analysis found that in all the electrolytes both β-MnO{sub 2} and MnOOH modified GCE electrodes exhibit electrochemical behavior and KCl shows well redox properties as compared with others. There is also an observable difference in reduction potential value of both crystalline nanostructurers and concluded that β-MnO{sub 2} has high catalytic ability as compared with MnOOH rods.

  10. Inverse spin Hall effect in Pt/(Ga,Mn)As

    SciTech Connect (OSTI)

    Nakayama, H.; Chen, L.; Chang, H. W.; Ohno, H.; Matsukura, F.

    2015-06-01

    We investigate dc voltages under ferromagnetic resonance in a Pt/(Ga,Mn)As bilayer structure. A part of the observed dc voltage is shown to originate from the inverse spin Hall effect. The sign of the inverse spin Hall voltage is the same as that in Py/Pt bilayer structure, even though the stacking order of ferromagnetic and nonmagnetic layers is opposite to each other. The spin mixing conductance at the Pt/(Ga,Mn)As interface is determined to be of the order of 10{sup 19 }m{sup −2}, which is about ten times greater than that of (Ga,Mn)As/p-GaAs.

  11. DOE - Office of Legacy Management -- Twin Cities Ammunition - MN 0-01

    Office of Legacy Management (LM)

    Twin Cities Ammunition - MN 0-01 FUSRAP Considered Sites Site: TWIN CITIES AMMUNITION (MN.0-01) Eliminated from further consideration under FUSRAP - Referred to DOD Designated Name: Not Designated Alternate Name: None Location: New Brighton , Minnesota MN.0-01-1 Evaluation Year: 1987 MN.0-01-2 Site Operations: Site was formerly licensed under 10CFR 70 by the NRC. MN.0-01-1 MN.0-01-2 Site Disposition: Eliminated - No Authority - Referred to DOD MN.0-01-1 Radioactive Materials Handled: None

  12. Magnetic domain tuning and the emergence of bubble domains in the bilayer manganite La<mn>2mn>->2mn>xSr<mn>1mn>+>2mn>xMn>2mn>O>7mn>(x=<mn>0.32mn>)

    SciTech Connect (OSTI)

    Jeong, Juyoung; Yang, Ilkyu; Yang, Jinho; Ayala-Valenzuela, Oscar E.; Wulferding, Dirk; Zhou, J. -S.; Goodenough, John B.; de Lozanne, Alex; Mitchell, J. F.; Leon, Neliza; Movshovich, Roman; Jeong, Yoon Hee; Yeom, Han Woong; Kim, Jeehoon

    2015-08-17

    Here, we report a magnetic force microscopy study of the magnetic domain evolution in the layered manganite La2–2xSr1+2xMn2O7 (with x = 0.32). This strongly correlated electron compound is known to exhibit a wide range of magnetic phases, including a recently uncovered biskyrmion phase. We observe a continuous transition from dendritic to stripelike domains, followed by the formation of magnetic bubbles due to a field- and temperature-dependent competition between in-plane and out-of-plane spin alignments. The magnetic bubble phase appears at comparable field and temperature ranges as the biskyrmion phase, suggesting a close relation between both phases. Based on our real-space images we construct a temperature-field phase diagram for this composition.

  13. CaMn2Al10: Itinerant Mn magnetism on the verge of magnetic order

    SciTech Connect (OSTI)

    Steinke, L.; Simonson, J. W.; Yin, W. -G.; Smith, G. J.; Kistner-Morris, J. J.; Zellman, S.; Puri, A.; Aronson, M. C.

    2015-07-24

    We report the discovery of CaMn2Al10, a metal with strong magnetic anisotropy and moderate electronic correlations. Magnetization measurements find a Curie-Weiss moment of 0.83μB/Mn, significantly reduced from the Hund's rule value, and the magnetic entropy obtained from specific heat measurements is correspondingly small, only ≈ 9% of Rln2. These results imply that the Mn magnetism is highly itinerant, a conclusion supported by density functional theory calculations that find strong Mn-Al hybridization. Consistent with the layered nature of the crystal structure, the magnetic susceptibility χ is anisotropic below 20 K, with a maximum ratio of χ[010][001] ≈ 3.5. A strong power-law divergence χ(T) ~ T–1.2 below 20 K implies incipient ferromagnetic order, an Arrott plot analysis of the magnetization suggests a vanishing low Curie temperature TC ~ 0. Our experiments indicate that CaMn2Al10 is a rare example of a system where the weak and itinerant Mn-based magnetism is poised on the verge of order.

  14. Strong enhancement of s -wave superconductivity near a quantum critical point of Ca<mn>3mn>Ir>4mn>Sn>13mn>

    SciTech Connect (OSTI)

    Biswas, P. K.; Guguchia, Z.; Khasanov, R.; Chinotti, M.; Li, L.; Wang, Kefeng; Petrovic, C.; Morenzoni, E.

    2015-11-11

    We report microscopic studies by muon spin rotation/relaxation as a function of pressure of the Ca<mn>3mn>Ir>4mn>Sn>13mn> and Sr3Ir4Sn13 system displaying superconductivity and a structural phase transition associated with the formation of a charge density wave (CDW). Our findings show a strong enhancement of the superfluid density and a dramatic increase of the pairing strength above a pressure of ≈ 1.6 GPa giving direct evidence of the presence of a quantum critical point separating a superconducting phase coexisting with CDW from a pure superconducting phase. The superconducting order parameter in both phases has the same s-wave symmetry. In spite of the conventional phonon-mediated BCS character of the weakly correlated (Ca1-xSrx)3Ir4Sn13 system the dependence of the effective superfluid density on the critical temperature puts this compound in the “Uemura” plot close to unconventional superconductors. This system exemplifies that conventional BCS superconductors in the presence of competing orders or multi-band structure can also display characteristics of unconventional superconductors.

  15. Mn-Fe base and Mn-Cr-Fe base austenitic alloys

    DOE Patents [OSTI]

    Brager, Howard R.; Garner, Francis A.

    1987-01-01

    Manganese-iron base and manganese-chromium-iron base austenitic alloys designed to have resistance to neutron irradiation induced swelling and low activation have the following compositions (in weight percent): 20 to 40 Mn; up to about 15 Cr; about 0.4 to about 3.0 Si; an austenite stabilizing element selected from C and N, alone or in combination with each other, and in an amount effective to substantially stabilize the austenite phase, but less than about 0.7 C, and less than about 0.3 N; up to about 2.5 V; up to about 0.1 P; up to about 0.01 B; up to about 3.0 Al; up to about 0.5 Ni; up to about 2.0 W; up to about 1.0 Ti; up to about 1.0 Ta; and with the remainder of the alloy being essentially iron.

  16. Revealing the Restructured Surface of Li[Mn2]O4

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Amos, Charles D.; Roldan, Manuel A.; Varela, Maria; Goodenough, John B.; Ferreira, Paulo J.

    2016-03-29

    The spinel Revealing the Restructured Surface of Li[Mn2]O4 is a candidate cathode for a Li-ion battery, but its capacity fades over a charge/discharge cycle of Li1–x[Mn2]O4 (0 < x < 1) that is associated with a loss of Mn to the organic-liquid electrolyte. It is known that the disproportionation reaction 2Mn3+ = Mn2+ + Mn4+ occurs at the surface of a Mn spinel, and it is important to understand the atomic structure and composition of the surface of Revealing the Restructured Surface of Li[Mn2]O4 in order to understand how Mn loss occurs. We report a study of the surface reconstructionmore » of Revealing the Restructured Surface of Li[Mn2]O4 by aberration-corrected scanning transmission electron microscopy. The atomic structure coupled with Mn-valence and the distribution of the atomic ratio of oxygen obtained by electron energy loss spectroscopy reveals a thin, stable surface layer of Mn3O4, a subsurface region of Li1+x[Mn2]O4 with retention of bulk Li[Mn2]O4. We conclude that this observation is compatible with the disproportionation reaction coupled with oxygen deficiency and a displacement of surface Li+ from the Mn3O4 surface phase. These results provide a critical step toward understanding how Mn is lost from Li[Mn2]O4, once inside a battery.« less

  17. Structure and magnetic properties of LnMnSbO ( Ln=La and Ce)

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Qiang; Kumar, C. M. N.; Tian, Wei; Dennis, Kevin W.; Goldman, Alan I.; Vaknin, David

    2016-03-11

    Here, a neutron powder diffraction (NPD) study of LnMnSbO (Ln = La or Ce) reveals differences between the magnetic ground state of the two compounds due to the strong Ce-Mn coupling compared to La-Mn. The two compounds adopt the P4/nmm space group down to 2 K, and whereas magnetization measurements do not show obvious anomaly at high temperatures, NPD reveals a C-type antiferromagnetic (AFM) order below TN = 255K for LaMnSbO and 240 K for CeMnSbO. While the magnetic structure of LaMnSbO is preserved to base temperature, a sharp transition at TSR = 4.5K is observed in CeMnSbO due tomore » a spin-reorientation (SR) transition of the Mn2+ magnetic moments from pointing along the c axis to the ab plane. The SR transition in CeMnSbO is accompanied by a simultaneous long-range AFM ordering of the Ce moments, which indicates that the Mn SR transition is driven by the Ce-Mn coupling. The ordered moments are found to be somewhat smaller than those expected for Mn2+ (S = 5/2) in insulators, but large enough to suggest that these compounds belong to the class of local-moment antiferromagnets. The lower TN found in these two compounds compared to the As-based counterparts (TN = 317 for LaMnAsO, TN = 347K for CeMnAsO) indicates that the Mn-Pn (Pn=As or Sb) hybridization that mediates the superexchange Mn-Pn-Mn coupling is weaker for the Sb-based compounds.« less

  18. Synthesis, characterization and electrochemical performance of Al-substituted Li₂MnO₃

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dhital, Chetan; Huq, Ashfia; Paranthaman, Mariappan Parans; Manivannan, Ayyakkannu; Torres-Castro, Loraine; Shojan, Jifi; Julien, Christian M.; Katiyar, Ram S.

    2015-08-08

    Li2MnO3 is known to be electrochemically inactive due to Mn in tetravalent oxidation state. Several compositions such as Li2MnO3 , Li1.5Al0.17MnO3, Li1.0Al0.33MnO3 and Li0.5Al0.5MnO3 were synthesized by a sol–gel Pechini method. All the samples were characterized with x-ray diffraction, Raman, x-ray photoelectron spectroscopy, scanning electron microscopy, Tap density and BET analyzer. X-ray diffraction patterns indicated the presence of monoclinic phase for pristine Li2MnO3and mixed monoclinic/spinel phases (Li2 - xMn1 - yAlx + yO3 + z) for Al-substituted Li2MnO3compounds. The Al substitution seems to occur both at Li and Mn sites, which could explain the presence of spinel phase. X-ray photoelectronmore » spectroscopy for Mn 2p orbital reveals a significant decrease in binding energy for Li1.0Al0.33MnO3 and Li0.5Al0.5MnO3 compounds. Cyclic voltammetry, charge/discharge cycles and electrochemical impedance spectroscopy were also performed. A discharge capacity of 24 mAh g-1 for Li2MnO3, 68 mAh g-1 for Li1.5Al0.17MnO3, 58 mAh g-1 for Li1.0Al0.33MnO3 and 74 mAh g-1 for Li0.5Al0.5MnO3 were obtained. As a result, aluminum substitutions increased the formation of spinel phase which is responsible for cycling.« less

  19. Resonant spin tunneling in randomly oriented nanospheres of Mn?? acetate

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lendinez, S.; Billinge, S. J. L.; Zarzuela, R.; Tejada, J.; Terban, M. W.; Espin, J.; Imaz, I.; Maspoch, D.; Chudnovsky, E. M.

    2015-01-06

    We report measurements and theoretical analysis of resonant spin tunneling in randomly oriented nanospheres of a molecular magnet. Amorphous nanospheres of Mn?? acetate have been fabricated and characterized by chemical, infrared, TEM, X-ray, and magnetic methods. Magnetic measurements have revealed sharp tunneling peaks in the field derivative of the magnetization that occur at the typical resonant field values for the Mn?? acetate crystal in the field parallel to the easy axis.Theoretical analysis is provided that explains these observations. We argue that resonant spin tunneling in a molecular magnet can be established in a powder sample, without the need for amoresingle crystal and without aligning the easy magnetization axes of the molecules. This is confirmed by re-analyzing the old data on a powdered sample of non-oriented micron-size crystals of Mn?? acetate. Our findings can greatly simplify the selection of candidates for quantum spin tunneling among newly synthesized molecular magnets.less

  20. Coexistence of charge-density wave and ferromagnetism in Ni2MnGa...

    Office of Scientific and Technical Information (OSTI)

    Coexistence of charge-density wave and ferromagnetism in Ni2MnGa Citation Details In-Document Search Title: Coexistence of charge-density wave and ferromagnetism in Ni2MnGa ...

  1. Stress induced anisotropy in CoFeMn soft magnetic nanocomposites...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Stress induced anisotropy in CoFeMn soft magnetic nanocomposites Citation Details In-Document Search Title: Stress induced anisotropy in CoFeMn soft magnetic ...

  2. Pulsed laser deposition of Mn doped CdSe quantum dots for improved solar cell performance

    SciTech Connect (OSTI)

    Dai, Qilin; Wang, Wenyong E-mail: jtang2@uwyo.edu; Tang, Jinke E-mail: jtang2@uwyo.edu; Sabio, Erwin M.

    2014-05-05

    In this work, we demonstrate (1) a facile method to prepare Mn doped CdSe quantum dots (QDs) on Zn{sub 2}SnO{sub 4} photoanodes by pulsed laser deposition and (2) improved device performance of quantum dot sensitized solar cells of the Mn doped QDs (CdSe:Mn) compared to the undoped QDs (CdSe). The band diagram of photoanode Zn{sub 2}SnO{sub 4} and sensitizer CdSe:Mn QD is proposed based on the incident-photon-to-electron conversion efficiency (IPCE) data. Mn-modified band structure leads to absorption at longer wavelengths than the undoped CdSe QDs, which is due to the exchange splitting of the CdSe:Mn conduction band by the Mn dopant. Three-fold increase in the IPCE efficiency has also been observed for the Mn doped samples.

  3. Pulsed laser deposition of Mn doped CdSe quantum dots for improved...

    Office of Scientific and Technical Information (OSTI)

    Pulsed laser deposition of Mn doped CdSe quantum dots for improved solar cell performance Citation Details In-Document Search Title: Pulsed laser deposition of Mn doped CdSe ...

  4. Mixing antiferromagnets to tune NiFe-[IrMn/FeMn] interfacial spin-glasses, grains thermal stability, and related exchange bias properties

    SciTech Connect (OSTI)

    Akmaldinov, K.; Ducruet, C.; Portemont, C.; Joumard, I.; Prejbeanu, I. L.; Dieny, B.; Baltz, V.

    2014-05-07

    Spintronics devices and in particular thermally assisted magnetic random access memories require a wide range of ferromagnetic/antiferromagnetic (F/AF) exchange bias (EB) properties and subsequently of AF materials to fulfil diverse functionality requirements for the reference and storage. For the reference layer, large EB energies and high blocking temperature (T{sub B}) are required. In contrast, for the storage layer, mostly moderate T{sub B} are needed. One of the present issues is to find a storage layer with properties intermediate between those of IrMn and FeMn and in particular: (i) with a T{sub B} larger than FeMn for better stability at rest-T but lower than IrMn to reduce power consumption at write-T and (ii) with improved magnetic interfacial quality, i.e., with reduced interfacial glassy character for lower properties dispersions. To address this issue, the EB properties of F/AF based stacks were studied for various mixed [IrMn/FeMn] AFs. In addition to EB loop shifts, the F/AF magnetic interfacial qualities and the AF grains thermal stability are probed via measurements of the low- and high-temperature contributions to the T{sub B} distributions, respectively. A tuning of the above three parameters is observed when evolving from IrMn to FeMn via [IrMn/FeMn] repetitions.

  5. Epitaxial growth of intermetallic MnPt films on oxides and large exchange bias

    SciTech Connect (OSTI)

    Liu, Zhiqi; Biegalski, Michael D.; Hsu, Shang-Lin; Shang, Shunli; Marker, Cassie; Liu, Jian; Li, Li; Fan, Lisha S.; Meyer, Tricia L.; Wong, Anthony T.; Nichols, John A.; Chen, Deyang; You, Long; Chen, Zuhuang; Wang, Kai; Wang, Kevin; Ward, Thomas Z.; Gai, Zheng; Lee, Ho Nyung; Sefat, Athena S.; Lauter, Valeria; Liu, Zi-kui; Christen, Hans M.

    2015-11-05

    High-quality epitaxial growth of intermetallic MnPt films on oxides is achieved, with potential for multiferroic heterostructure applications. Antisite-stabilized spin-flipping induces ferromagnetism in MnPt films, although it is robustly antiferromagnetic in bulk. Thus, highly ordered antiferromagnetic MnPt films exhibit superiorly large exchange coupling with a ferromagnetic layer.

  6. Epitaxial Growth of Intermetallic MnPt Films on Oxides and Large Exchange Bias

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Liu, Zhiqi; Biegalski, Michael D.; Hsu, Shang-Lin; Shang, Shunli; Marker, Cassie; Liu, Jian; Li, Li; Fan, Lisha S.; Meyer, Tricia L.; Wong, Anthony T.; et al

    2015-11-05

    High-quality epitaxial growth of intermetallic MnPt films on oxides is achieved, with potential for multiferroic heterostructure applications. Antisite-stabilized spin-flipping induces ferromagnetism in MnPt films, although it is robustly antiferromagnetic in bulk. Moreover, highly ordered antiferromagnetic MnPt films exhibit superiorly large exchange coupling with a ferromagnetic layer.

  7. Cationic disorder and Mn{sup 3+}/Mn{sup 4+} charge ordering in the B? and B? sites of Ca{sub 3}Mn{sub 2}NbO{sub 9} perovskite: a comparison with Ca{sub 3}Mn{sub 2}WO{sub 9}

    SciTech Connect (OSTI)

    Lpez, C.A.; Saleta, M.E.; Pedregosa, J.C.; Snchez, R.D.; Alonso, J.A.; and others

    2014-02-15

    We describe the preparation, crystal structure determination, magnetic and transport properties of two novel Mn-containing perovskites, with a different electronic configuration for Mn atoms located in B site. Ca{sub 3}Mn{sup 3+}{sub 2}WO{sub 9} and Ca{sub 3}Mn{sup 3+/4+}{sub 2}NbO{sub 9} were synthesized by standard ceramic procedures; the crystallographic structure was studied from X-ray powder diffraction (XRPD) and neutron powder diffraction (NPD). Both phases exhibit a monoclinic symmetry (S.G.: P2{sub 1}/n); Ca{sub 3}Mn{sub 2}WO{sub 9} presents a long-range ordering over the B sites, whereas Ca{sub 3}Mn{sub 2}NbO{sub 9} is strongly disordered. By in-situ NPD, the temperature evolution of the structure study presents an interesting evolution in the octahedral size (?MnO?) for Ca{sub 3}Mn{sub 2}NbO{sub 9}, driven by a charge ordering effect between Mn{sup 3+} and Mn{sup 4+} atoms, related to the anomaly observed in the transport measurements at T?160 K. Both materials present a magnetic order below T{sub C}=30 K and 40 K for W and Nb materials, respectively. The magneto-transport measurements display non-negligible magnetoresistance properties in the paramagnetic regime. - Graphical abstract: Comparison between the octahedron size and the magnetic behaviour for Ca{sub 3}Mn{sub 2}NbO{sub 9} in the temperature region where the charge and magnetic order occur. Display Omitted - Highlights: Two novel Mn-containing double perovskites were obtained by solid-state reactions. Both double perovskites are monoclinic (P2{sub 1}/n) determined by XRPD and NPD. Ca{sub 3}Mn{sub 2}WO{sub 9} contains Mn{sup 3+} while Ca{sub 3}Mn{sub 2}NbO{sub 9} includes mixed-valence cations Mn{sup 3+}/Mn{sup 4+}. Ca{sub 3}Mn{sub 2}NbO{sub 9} presents a charge-ordering effect between Mn{sup 3+} and Mn{sup 4+} evidenced by NPD. The magnetic and transport studies evidenced the charge ordering in Ca{sub 3}Mn{sub 2}NbO{sub 9}.

  8. Neutron scattering study of spin ordering and stripe pinning in superconducting La<mn>1.93mn>Sr>0.07mn>CuO>4mn>

    SciTech Connect (OSTI)

    Jacobsen, H.; Zaliznyak, I. A.; Savici, A. T.; Winn, B. L.; Chang, S.; Hücker, M.; Gu, G. D.; Tranquada, J. M.

    2015-11-20

    The relationships among charge order, spin fluctuations, and superconductivity in underdoped cuprates remain controversial. We use neutron scattering techniques to study these phenomena in La<mn>1.93mn>Sr>0.07mn>CuO>4mn> a superconductor with a transition temperature of Tc = 20 K. At T<< Tc, we find incommensurate spin fluctuations with a quasielastic energy spectrum and no sign of a gap within the energy range from 0.2 to 15 meV. A weak elastic magnetic component grows below ~ 10 K, consistent with results from local probes. Regarding the atomic lattice, we have discovered unexpectedly strong fluctuations of the CuO6 octahedra about Cu-O bonds, which are associated with inequivalent O sites within the CuO2 planes. Moreover, we observed a weak elastic (3 30) superlattice peak that implies a reduced lattice symmetry. The presence of inequivalent O sites rationalizes various pieces of evidence for charge stripe order in underdoped La2-xSrxCuO4. The coexistence of superconductivity with quasi-static spin-stripe order suggests the presence of intertwined orders; however, the rotation of the stripe orientation away from the Cu-O bonds might be connected with evidence for a finite gap at the nodal points of the superconducting gap function.

  9. Clarification of enhanced ferromagnetism in Be-codoped InMnP fabricated using Mn/InP:Be bilayers grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Shon, Yoon; Lee, Sejoon; Taek Yoon, Im; Jeon, H. C.; Lee, D. J.; Kang, T. W.; Song, J. D.; Yoon, Chong S.; Kim, D. Y.; Park, C. S.

    2011-11-07

    The p-type InMnP:Be epilayers were prepared by the sequential growth of Mn/InP:Be bilayers using molecular-beam-epitaxy and the subsequent in-situ annealing at 200-300 deg. C. In triple-axis x-ray diffraction patterns, the samples revealed a shoulder peak indicative of intrinsic InMnP. The ferromagnetic transition in InMnP:Be was observed to occur at the elevated temperature of {approx}140 K, and the ferromagnetic spin-domains clearly appeared in magnetic force microscopy images. The improved ferromagnetic properties are attributed to the increased p-d hybridation due to high p-type conductivity of InMnP:Be (p {approx} 10{sup 20 }cm{sup -3}). The results suggest that enhanced ferromagnetism can be effectively obtained from Be-codoped InMnP.

  10. Magnetic properties of α−MnO{sub 2} and Co-doped α−MnO{sub 2} nanowires

    SciTech Connect (OSTI)

    Stella, C. Soundararajan, N. Ramachandran, K.

    2014-04-24

    α−MnO{sub 2} and Co-doped α−MnO{sub 2} nanowires (NWs) were synthesized by hydrothermal method. The structural characterization by XRD revealed the tetragonal structure of α−MnO{sub 2}. The formation of one dimensional (1D) NWs of pure and Co-doped α−MnO{sub 2} was confirmed from SEM. From UV-Vis absorption spectra, it is found that both pure and Co-doped α−MnO{sub 2} NWs showed blue shift compared to bulk, which revealed the quantum confinement in the synthesized samples. The magnetic properties were analyzed by VSM, which suggest that pure and doped α−MnO{sub 2} exhibit ferromagnetic behavior at room temperature (RT)

  11. Effect of Mn substitution on the transport properties of co-sputtered Fe{sub 3−x}Mn{sub x}Si epilayers

    SciTech Connect (OSTI)

    Tang, M.; Jin, C.; Bai, H. L.

    2014-11-07

    Motivated by the theoretical calculations that Fe{sub 3−x}Mn{sub x}Si can simultaneously exhibit a high spin polarization with a high Curie temperature to be applied in spintronic devices, and in order to further study the effect of Mn contents on the physical properties of Fe{sub 3−x}Mn{sub x}Si, we have investigated the effect of Mn substitution on the transport properties of epitaxial Fe{sub 3−x}Mn{sub x}Si (0≤x≤1) films systematically. The Fe{sub 3−x}Mn{sub x}Si films were epitaxially grown on MgO(001) plane with 45° rotation. The magnetization for various x shows enhanced irreversibility, implying the antiferromagnetic ordering induced by the substitution of Mn. A metal-semiconductor crossover was observed due to the enhanced disorders of interactions and the local lowering of symmetry induced by the substitution of Mn. The single-domain state in the Fe{sub 3−x}Mn{sub x}Si films leads to twofold symmetric curves of the anisotropic magnetoresistance and planar Hall resistivity.

  12. Role of t{sub 2g} electrons in Mn-Tb coupling of multiferroic TbMnO{sub 3}

    SciTech Connect (OSTI)

    Guo, Y. Y.; Wang, Y. L.; Liu, J.-M.; Wei, T.

    2014-08-14

    We investigate the effect of Cr-doping in polycrystalline TbMn{sub 1?x}Cr{sub x}O{sub 3} (x???6%) ceramics on the magnetism, ferroelectricity, and dielectricity. The Cr substitution gradually suppresses the ferroelectricity induced by the Mn spiral spin ordering, and results in a stronger modulation of polarization by magnetic field with increasing x. However, the transition temperature T{sub Tb} corresponding to onset of Tb magnetic ordering has barely shifted with Cr doping. In other words, although the Cr-doping obviously disrupts the Mn spiral spin ordering, the exchange field J{sub Mn-Tb} acting on the Tb moments from the Mn-spin structure is hardly impacted. Our work demonstrates that the e{sub g} electron of Mn{sup 3+} plays an important role in forming the Mn spiral spin order, but the f-d exchange interaction between the Mn 3d spins and the Tb 4f moments in multiferroic TbMnO{sub 3} almost involves only the t{sub 2g} electrons.

  13. Plutonium Oxidation and Subsequent Reduction by Mn (IV) Minerals

    SciTech Connect (OSTI)

    KAPLAN, DANIEL

    2005-09-13

    Plutonium sorbed to rock tuff was preferentially associated with manganese oxides. On tuff and synthetic pyrolusite (Mn{sup IV}O{sub 2}), Pu(IV) or Pu(V) was initially oxidized, but over time Pu(IV) became the predominant oxidation state of sorbed Pu. Reduction of Pu(V/VI), even on non-oxidizing surfaces, is proposed to result from a lower Gibbs free energy of the hydrolyzed Pu(IV) surface species versus that of the Pu(V) or Pu(VI) surface species. This work suggests that despite initial oxidation of sorbed Pu by oxidizing surfaces to more soluble forms, the less mobile form of Pu, Pu(IV), will dominate Pu solid phase speciation during long term geologic storage. The safe design of a radioactive waste or spent nuclear fuel geologic repository requires a risk assessment of radionuclides that may potentially be released into the surrounding environment. Geochemical knowledge of the radionuclide and the surrounding environment is required for predicting subsurface fate and transport. Although difficult even in simple systems, this task grows increasingly complicated for constituents, like Pu, that exhibit complex environmental chemistries. The environmental behavior of Pu can be influenced by complexation, precipitation, adsorption, colloid formation, and oxidation/reduction (redox) reactions (1-3). To predict the environmental mobility of Pu, the most important of these factors is Pu oxidation state. This is because Pu(IV) is generally 2 to 3 orders of magnitude less mobile than Pu(V) in most environments (4). Further complicating matters, Pu commonly exists simultaneously in several oxidation states (5, 6). Choppin (7) reported Pu may exist as Pu(IV), Pu(V), or Pu(VI) oxic natural groundwaters. It is generally accepted that plutonium associated with suspended particulate matter is predominantly Pu(IV) (8-10), whereas Pu in the aqueous phase is predominantly Pu(V) (2, 11-13). The influence of the character of Mn-containing minerals expected to be found in subsurface

  14. Relation between the magnetization and the electrical properties of alloy GaSb-MnSb films

    SciTech Connect (OSTI)

    Koplak, O. V.; Polyakov, A. A.; Davydov, A. B.; Morgunov, R. B.; Talantsev, A. D.; Kochura, A. V.; Fedorchenko, I. V.; Novodvorskii, O. A.; Parshina, L. S.; Khramova, O. D.; Shorokhova, A. V.; Aronzon, B. A.

    2015-06-15

    The influence of the charge carrier concentration on the magnetic properties of GaSb-MnSb alloys is studied. The ferromagnetism of GaSb-MnSb films is caused by the presence of MnSb granules and manifests itself in both magnetometric measurements and the presence of an anisotropic magnetoresistance and the anomalous Hall effect. Electric conduction is executed by charge carriers (holes) in a GaSb matrix. The magnetization of clusters depends on stoichiometry and the concentration of Mn{sup 2+} and Mn{sup 3+} ions, which is specified by the film growth conditions. At high film growth temperatures, ferromagnetic clusters containing Mn{sup 2+} ions mainly form. At low growth temperatures, an antiferromagnetic phase containing Mn{sup 3+} ions forms.

  15. Effect of Composition and Heat Treatment on MnBi Magnetic Materials

    SciTech Connect (OSTI)

    Cui, Jun; Choi, Jung-Pyung; Polikarpov, Evgueni; Bowden, Mark E.; Xie, Wei; Li, Guosheng; Nie, Zimin; Zarkevich, Nikolai; Kramer, Matthew J.; Johnson, Duane D.

    2014-08-17

    The metallic compound MnBi is a promising rare-earth-free permanent magnet material. Compare to other rare-earth-free candidates, MnBi stands out for its high intrinsic coercivity (Hci) and its large positive temperature coefficient. Several groups have demonstrated that the Hci of MnBi compound in thin film or in powder form can exceed 12 kOe and 26 kOe at 300 K and 523 K, respectively. Such steep increase in Hci with increasing temperature is unique to MnBi. Consequently, MnBi is a highly sought-after hard phase for exchange coupling nanocomposite magnets. The reaction between Mn and Bi is peritectic, so Mn tends to precipitate out of the MnBi liquid during the solidification process. As result, the composition of the Mn-Bi alloy with the largest amount of the desired LTP (low temperature phase) MnBi and highest saturation magnetization will be over-stoichiometric and rich in Mn. The amount of additional Mn required to compensate the Mn precipitation depends on solidification rate: the faster the quench speed, the less Mn precipitates. Here we report a systematic study of the effect of composition and heat treatments on the phase contents and magnetic properties of Mn-Bi alloys. In this study, Mn-Bi alloys with 14 compositions were prepared using conventional metallurgical methods such as arc melting and vacuum heat treatment, and the obtained alloys were analyzed for compositions, crystal structures, phase content, and magnetic properties. The results show that the composition with 55 at.% Mn exhibits the highest LTP MnBi content and the highest magnetization. The sample with this composition shows >90 wt.% LTP MnBi content. Its measured saturation magnetization is 68 emu/g with 2.3 T applied field at 300 K; its coercivity is 13 kOe and its energy product is 12 MGOe at 300 K. A bulk magnet fabricated using this powder exhibits an energy product of 8.2 MGOe.

  16. Magnetostructural phase transformations in Tb 1-x Mn 2

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zou, Junding; Paudyal, Durga; Liu, Jing; Mudryk, Yaroslav; Pecharsky, Vitalij K.; Gschneidner, Karl A.

    2015-01-16

    Magnetism and phase transformations in non-stoichiometric Tb1-xMn2 (x = 0.056, 0.039) have been studied as functions of temperature and magnetic field using magnetization, heat capacity, and X-ray powder diffraction measurements. Lowering the temperature, the compounds sequentially order ferrimagnetically and antiferromagnetically, and finally, exhibit spin reorientation transitions. Moreover, these structural distortions from room temperature cubic to low temperature rhombohedral structures occur at TN, and are accompanied by large volume changes reaching ~-1.27% and -1.42%, respectively. First principles electronic structure calculations confirm the phase transformation from the ferrimagnetic cubic structure to the antiferromagnetic rhombohedral structure in TbMn2.

  17. On the state of Mn impurity implanted in Si

    SciTech Connect (OSTI)

    Orlov, A. F.; Bublik, V. T.; Vdovin, V. I.; Agafonov, Yu. A.; Balagurov, L. A.; Zinenko, V. I.; Kulemanov, I. V.; Shcherbachev, K. D.

    2009-07-15

    The state of manganese impurity in implanted silicon at implantation doses of up to 5 x 10{sup 16} cm{sup -2} has been investigated by X-ray diffraction and transmission electron microscopy. It is established that, after short-term vacuum annealing at 850{sup o}C, most of the implanted manganese impurities are in microinclusions up to 20 nm in size formed by a tetragonal silicide phase of the Mn{sub 15}Si{sub 26} type.

  18. High-pressure structural study of MnF2

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Stavrou, Elissaios; Yao, Yansun; Goncharov, Alexander F.; Konopkova, Zuzana; Raptis, Constantine

    2015-02-01

    In this study, manganese fluoride (MnF2) with the tetragonal rutile-type structure has been studied using a synchrotron angle-dispersive powder x-ray diffraction and Raman spectroscopy in a diamond anvil cell up to 60 GPa at room temperature combined with first-principles density functional calculations. The experimental data reveal two pressure-induced structural phase transitions with the following sequence: rutile → SrI2 type (3 GPa)→ α–PbCl2 type (13 GPa). Complete structural information, including interatomic distances, has been determined in the case of MnF2 including the exact structure of the debated first high-pressure phase. First-principles density functional calculations confirm this phase transition sequence, and themore » two calculated transition pressures are in excellent agreement with the experiment. Lattice dynamics calculations also reproduce the experimental Raman spectra measured for the ambient and high-pressure phases. The results are discussed in line with the possible practical use of rutile-type fluorides in general and specifically MnF2 as a model compound to reveal the HP structural behavior of rutile-type SiO2 (Stishovite).« less

  19. Ferromagnetic interactions and martensitic transformation in Fe doped Ni-Mn-In shape memory alloys

    SciTech Connect (OSTI)

    Lobo, D. N.; Priolkar, K. R.; Emura, S.; Nigam, A. K.

    2014-11-14

    The structure, magnetic, and martensitic properties of Fe doped Ni-Mn-In magnetic shape memory alloys have been studied by differential scanning calorimetry, magnetization, resistivity, X-ray diffraction (XRD), and EXAFS. While Ni{sub 2}MnIn{sub 1?x}Fe{sub x} (0???x???0.6) alloys are ferromagnetic and non martensitic, the martensitic transformation temperature in Ni{sub 2}Mn{sub 1.5}In{sub 1?y}Fe{sub y} and Ni{sub 2}Mn{sub 1.6}In{sub 1?y}Fe{sub y} increases for lower Fe concentrations (y???0.05) before decreasing sharply for higher Fe concentrations. XRD analysis reveals presence of cubic and tetragonal structural phases in Ni{sub 2}MnIn{sub 1?x}Fe{sub x} at room temperature with tetragonal phase content increasing with Fe doping. Even though the local structure around Mn and Ni in these Fe doped alloys is similar to martensitic Mn rich Ni-Mn-In alloys, presence of ferromagnetic interactions and structural disorder induced by Fe affect Mn-Ni-Mn antiferromagnetic interactions resulting in suppression of martensitic transformation in these Fe doped alloys.

  20. Manganese valence and coordination structure in Mn,Mg-codoped {gamma}-AlON green phosphor

    SciTech Connect (OSTI)

    Takeda, Takashi; Xie, Rong-Jun; Hirosaki, Naoto; Matsushita, Yoshitaka; Honma, Tetuso

    2012-10-15

    The valence and coordination structure of manganese in a Mn,Mg-codoped {gamma}-AlON spinel-type oxynitride green phosphor were studied by synchrotron X-ray diffraction and absorption fine structure measurements. The absorption edge position of the XANES revealed the bivalency of Mn. Two cation sites are available in the spinel structure for cation doping: a tetrahedral site and an octahedral site. The pre-edge of the XANES and the distance to the nearest neighbor atoms obtained from the EXAFS measurement showed that Mn was situated at the tetrahedral site. Rietveld analysis showed that the vacancy occupied the octahedral site. The preferential occupation of the tetrahedral site by Mn and the roles of N and Mg are discussed in relation to the spinel crystal structure. - Graphical Abstract: Fourier transform of EXAFS of Mn K-edge for Mn,Mg-codoped green phosphor and Mn coordination structure. Highlights: Black-Right-Pointing-Pointer Mn, Mg-codoped {gamma}-AlON green phosphor for white LED. Black-Right-Pointing-Pointer The valence of Mn is divalent. Black-Right-Pointing-Pointer Mn occupies the tetrahedral site in the spinel structure.

  1. Dynamic study of (De)sodiation in alpha-MnO2 nanowires

    SciTech Connect (OSTI)

    Yuan, Yifei; Ma, Lu; He, Kun; Yao, Wentao; Nie, Anmin; Bi, Xuanxuan; Amine, Khalil; Wu, Tianpin; Lu, Jun; Shahbazian-Yassr, Reza

    2016-01-01

    In this report, the electrochemical sodiation and desodiation in single crystalline alpha-MnO2 nanowires are studied dynamically at both single particle level using in situ transmission electron microscopy (TEM) and bulk level using in situ synchrotron X-ray. The TEM results suggest that the first sodiation process starts with tunnel-based Na+ intercalation, experiences the formation of Na0.5MnO2 as a result of tunnel degradation, and ends with the Mn2O3 phase. The inserted Na+ can be partially extracted out of the sodiated products, and the following cycles are dominated by the reversible conversion reaction between Na0.5MnO2 and Mn2O3. The Mn valence evolution inside a cycling coin using alpha-MnO2 nanowire electrode also exhibits partially reversible characteristic, agreeing well with the in situ TEM analysis. The sodiation is compared with lithiation in the same alpha-MnO2 nanowires. Both Na+ and Li+ interact with the tunneled structure via a similar tunnel -driven intercalation mechanism before Mn4+ is reduced to Mn3.5+. For the following deep insertion, the tunnels survive up. to LiMnO2 (Mn3+) during lithiation, while the sodiation proceeds via a different mechanism that involves obvious phase transition and fast tunnel degradation after Mn's valence is below 3.5+. The difference in charge carrier insertion mechanisms can be ascribed to the strong interaction between the tunnel frame and inserted Na+ possessing a larger ionic size than inserted Li+.

  2. Effect of composition and heat treatment on MnBi magnetic materials

    SciTech Connect (OSTI)

    Cui, Jun [Pacific Northwest National Laboratory; Choi, Jung-Pyung [Pacific Northwest National Laboratory; Polikarpov, Evgueni [Pacific Northwest National Laboratory; Bowden, Mark E [Pacific Northwest National Laboratory; Xie, Wei [Pacific Northwest National Laboratory; Li, Guosheng [Pacific Northwest National Laboratory; Nie, Zimin [Pacific Northwest National Laboratory; Zarkevich, Nikolai [Ames Laboratory; Kramer, Matthew J [Ames Laboratory; Johnson, Duane [Ames Laboratory

    2014-10-01

    The metallic compound MnBi is a promising rare-earth-free permanent magnet material, unique among all candidates for its high intrinsic coercivity (Hci) and its large positive temperature coefficient. The Hci of MnBi in thin-film or powder form can exceed 12 and 26 kOe at 300 and 523 K, respectively. Such a steep rise in Hci with increasing temperature is unique to MnBi. Consequently, MnBi is a highly sought-after hard phase for exchange coupling nanocomposite magnets. However, the reaction between Mn and Bi is peritectic, and hence Mn tends to precipitate out of the MnBi liquid during the solidification process. As result, when the alloy is prepared using conventional induction or arc-melting casting methods, additional Mn is required to compensate the precipitation of Mn. In addition to composition, post-casting annealing plays an important role in obtaining a high content of MnBi low-temperature phase (LTP) because the annealing encourages the Mn precipitates and the unreacted Bi to react, forming the desired LTP phase. Here we report a systematic study of the effect of composition and heat treatments on the phase content and magnetic properties of MnBi alloys. In this study, 14 compositions were prepared using conventional metallurgical methods, and the compositions, crystal structures, phase content and magnetic properties of the resulting alloys were analyzed. The results show that the composition with 55 at.% Mn exhibits both the highest LTP content (93 wt.%) and magnetization (74 emu g?1 with 9 T applied field at 300 K).

  3. Large exchange bias enhancement in (Pt(or Pd)/Co)/IrMn/Co trilayers with ultrathin IrMn thanks to interfacial Cu dusting

    SciTech Connect (OSTI)

    Vinai, G. [SPINTEC, UMR 8191 CEA/CNRS/UJF/Grenoble-INP, CEA/INAC, 17, rue des Martyrs, 38054 Grenoble (France); Crocus Technology, 4 Place Robert Schuman, 38054 Grenoble (France); Moritz, J. [Institut Jean Lamour, UMR 7198 CNRS - Universit de Lorraine, Bd des Aiguillettes, BP 70239, F-54506 Vandoeuvre-les-Nancy Cedex (France); Bandiera, S. [Crocus Technology, 4 Place Robert Schuman, 38054 Grenoble (France); Prejbeanu, I. L.; Dieny, B. [SPINTEC, UMR 8191 CEA/CNRS/UJF/Grenoble-INP, CEA/INAC, 17, rue des Martyrs, 38054 Grenoble (France)

    2014-04-21

    The magnitude of exchange bias (H{sub ex}) at room temperature can be significantly enhanced in IrMn/Co and (Pt(or Pd)/Co)/IrMn/Co structures thanks to the insertion of an ultrathin Cu dusting layer at the IrMn/Co interface. The combination of trilayer structure and interfacial Cu dusting leads to a three-fold increase in H{sub ex} as compared to the conventional IrMn/Co bilayer structure, with an increased blocking temperature (T{sub B}) and a concave curvature of the temperature dependence H{sub ex}(T), ideal for improved Thermally Assisted-Magnetic Random Access Memory storage layer. This exchange bias enhancement is ascribed to a reduction of the spin frustration at the IrMn/Co interface thanks to interfacial Cu addition.

  4. Synthesis, characterization and electrochemical performance of Al-substituted Li₂MnO₃

    SciTech Connect (OSTI)

    Dhital, Chetan; Huq, Ashfia; Paranthaman, Mariappan Parans; Manivannan, Ayyakkannu; Torres-Castro, Loraine; Shojan, Jifi; Julien, Christian M.; Katiyar, Ram S.

    2015-08-08

    Li2MnO3 is known to be electrochemically inactive due to Mn in tetravalent oxidation state. Several compositions such as Li2MnO3 , Li1.5Al0.17MnO3, Li1.0Al0.33MnO3 and Li0.5Al0.5MnO3 were synthesized by a sol–gel Pechini method. All the samples were characterized with x-ray diffraction, Raman, x-ray photoelectron spectroscopy, scanning electron microscopy, Tap density and BET analyzer. X-ray diffraction patterns indicated the presence of monoclinic phase for pristine Li2MnO3and mixed monoclinic/spinel phases (Li2 - xMn1 - yAlx + yO3 + z) for Al-substituted Li2MnO3compounds. The Al substitution seems to occur both at Li and Mn sites, which could explain the presence of spinel phase. X-ray photoelectron spectroscopy for Mn 2p orbital reveals a significant decrease in binding energy for Li1.0Al0.33MnO3 and Li0.5Al0.5MnO3 compounds. Cyclic voltammetry, charge/discharge cycles and electrochemical impedance spectroscopy were also performed. A discharge capacity of 24 mAh g-1 for Li2MnO3, 68 mAh g-1 for Li1.5Al0.17MnO3, 58 mAh g-1 for Li1.0Al0.33MnO3 and 74 mAh g-1 for Li0.5Al0.5MnO3 were obtained. As a result, aluminum substitutions increased the formation of spinel phase which is responsible for cycling.

  5. The magnetic origin of multiferroic Y{sub 2}CoMnO{sub 6}

    SciTech Connect (OSTI)

    Jia, Ting; Zeng, Zhi; Li, X. G.; Lin, H. Q.

    2015-05-07

    It has been found experimentally that the ferroelectricity in Y{sub 2}CoMnO{sub 6} is driven by a magnetic ordering of collinear up-up-down-down (↑↑↓↓). Here, the origin of the magnetism and thereby ferroelectricity is studied using first-principles calculations. We first confirm that the experimentally observed ↑↑↓↓ antiferromagnetic structure is the ground state of Y{sub 2}CoMnO{sub 6}. Additionally, both the Co{sup 2+} and Mn{sup 4+} are in the high-spin state. By analyzing the exchange coupling and corresponding pathways, we conclude that the ↑↑↓↓ spin order in Y{sub 2}CoMnO{sub 6} originates from a subtle competition between the ferromagnetic Co-O-Mn super-exchange and antiferromagnetic Co-Mn direct-exchange along c axis.

  6. Cr(OH)₃(s) Oxidation Induced by Surface Catalyzed Mn(II) Oxidation

    SciTech Connect (OSTI)

    Namgung, Seonyi; Kwon, M.; Qafoku, Nikolla; Lee, Gie Hyeon

    2014-09-16

    This study examined the feasibility of Cr(OH)₃(s) oxidation mediated by surface catalyzed Mn(II) oxidation under common groundwater pH conditions as a potential pathway of natural Cr(VI) contaminations. Dissolved Mn(II) (50 μM) was reacted with or without synthesized Cr(OH)₃(s) (1.0 g/L) at pH 7 – 9 under oxic or anoxic conditions. In the absence of Cr(OH)₃(s), homogeneous Mn(II) oxidation by dissolved O₂ was not observed at pH ≤ 8.0 for 50 d. At pH 9.0, by contrast, dissolved Mn(II) was completely removed within 8 d and precipitated as hausmannite. When Cr(OH)₃(s) was present, this solid was oxidized and released substantial amounts of Cr(VI) as dissolved Mn(II) was added into the suspension at pH ≥ 8.0 under oxic conditions. Our results suggest that Cr(OH)₃(s) was readily oxidized by a newly formed Mn oxide as a result of Mn(II) oxidation catalyzed on Cr(OH)₃(s) surface. XANES analysis of the residual solids after the reaction between 1.0 g/L Cr(OH)₃(s) and 204 μM Mn(II) at pH 9.0 for 22 d revealed that the product of surface catalyzed Mn(II) oxidation resembled birnessite. The rate and extent of Cr(OH)₃(s) oxidation was likely controlled by those of surface catalyzed Mn(II) oxidation as the production of Cr(VI) increased with increasing pH and initial Mn(II) concentrations. This study evokes the potential environmental hazard of sparingly soluble Cr(OH)₃(s) that can be a source of Cr(VI) in the presence of dissolved Mn(II).

  7. Structural and ferromagnetic properties of an orthorhombic phase of MnBi stabilized with Rh additions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Taufour, Valentin; Thimmaiah, Srinivasa; March, Stephen; Saunders, Scott; Sun, Kewei; Lamichhane, Tej Nath; Kramer, Matthew J.; Bud’ko, Sergey L.; Canfield, Paul C.

    2015-07-28

    The article addresses the possibility of alloy elements in MnBi which may modify the thermodynamic stability of the NiAs-type structure without significantly degrading the magnetic properties. The addition of small amounts of Rh and Mn provides an improvement in the thermal stability with some degradation of the magnetic properties. The small amounts of Rh and Mn additions in MnBi stabilize an orthorhombic phase whose structural and magnetic properties are closely related to the ones of the previously reported high-temperature phase of MnBi (HT MnBi). The properties of the HT MnBi, which is stable between 613 and 719 K, have notmore » been studied in detail because of its transformation to the stable low-temperature MnBi (LT MnBi), making measurements near and below its Curie temperature difficult. The Rh-stabilized MnBi with chemical formula Mn1.0625–xRhxBi [x=0.02(1)] adopts a new superstructure of the NiAs/Ni2In structure family. It is ferromagnetic below a Curie temperature of 416 K. The critical exponents of the ferromagnetic transition are not of the mean-field type but are closer to those associated with the Ising model in three dimensions. The magnetic anisotropy is uniaxial; the anisotropy energy is rather large, and it does not increase when raising the temperature, contrary to what happens in LT MnBi. The saturation magnetization is approximately 3μB/f.u. at low temperatures. Thus, while this exact composition may not be application ready, it does show that alloying is a viable route to modifying the stability of this class of rare-earth-free magnet alloys.« less

  8. Structural and ferromagnetic properties of an orthorhombic phase of MnBi stabilized with Rh additions

    SciTech Connect (OSTI)

    Taufour, Valentin; Thimmaiah, Srinivasa; March, Stephen; Saunders, Scott; Sun, Kewei; Lamichhane, Tej Nath; Kramer, Matthew J.; Bud’ko, Sergey L.; Canfield, Paul C.

    2015-07-28

    The article addresses the possibility of alloy elements in MnBi which may modify the thermodynamic stability of the NiAs-type structure without significantly degrading the magnetic properties. The addition of small amounts of Rh and Mn provides an improvement in the thermal stability with some degradation of the magnetic properties. The small amounts of Rh and Mn additions in MnBi stabilize an orthorhombic phase whose structural and magnetic properties are closely related to the ones of the previously reported high-temperature phase of MnBi (HT MnBi). The properties of the HT MnBi, which is stable between 613 and 719 K, have not been studied in detail because of its transformation to the stable low-temperature MnBi (LT MnBi), making measurements near and below its Curie temperature difficult. The Rh-stabilized MnBi with chemical formula Mn1.0625–xRhxBi [x=0.02(1)] adopts a new superstructure of the NiAs/Ni2In structure family. It is ferromagnetic below a Curie temperature of 416 K. The critical exponents of the ferromagnetic transition are not of the mean-field type but are closer to those associated with the Ising model in three dimensions. The magnetic anisotropy is uniaxial; the anisotropy energy is rather large, and it does not increase when raising the temperature, contrary to what happens in LT MnBi. The saturation magnetization is approximately 3μB/f.u. at low temperatures. Thus, while this exact composition may not be application ready, it does show that alloying is a viable route to modifying the stability of this class of rare-earth-free magnet alloys.

  9. Electronic Structure and Oxidation State Changes in the Mn (4) Ca Cluster of Photosystem II

    SciTech Connect (OSTI)

    Yano, J.; Pushkar, Y.; Messinger, J.; Bergmann, U.; Glatzel, P.; Yachandra, V.K.; /SLAC

    2012-08-17

    Oxygen-evolving complex (Mn{sub 4}Ca cluster) of Photosystem II cycles through five intermediate states (S{sub i}-states, i = 0-4) before a molecule of dioxygen is released. During the S-state transitions, electrons are extracted from the OEC, either from Mn or alternatively from a Mn ligand. The oxidation state of Mn is widely accepted as Mn{sub 4}(III{sub 2},IV{sub 2}) and Mn{sub 4}(III,IV{sub 3}) for S{sub 1} and S{sub 2} states, while it is still controversial for the S{sub 0} and S{sub 3} states. We used resonant inelastic X-ray scattering (RIXS) to study the electronic structure of Mn{sub 4}Ca complex in the OEC. The RIXS data yield two-dimensional plots that provide a significant advantage by obtaining both K-edge pre-edge and L-edge-like spectra (metal spin state) simultaneously. We have collected data from PSII samples in the each of the S-states and compared them with data from various inorganic Mn complexes. The spectral changes in the Mn 1s2p{sub 3/2} RIXS spectra between the S-states were compared to those of the oxides of Mn and coordination complexes. The results indicate strong covalency for the electronic configuration in the OEC, and we conclude that the electron is transferred from a strongly delocalized orbital, compared to those in Mn oxides or coordination complexes. The magnitude for the S{sub 0} to S{sub 1}, and S{sub 1} to S{sub 2} transitions is twice as large as that during the S{sub 2} to S{sub 3} transition, indicating that the electron for this transition is extracted from a highly delocalized orbital with little change in charge density at the Mn atoms.

  10. Preparation and electrochemical properties of lamellar MnO{sub 2} for supercapacitors

    SciTech Connect (OSTI)

    Yan, Jun; Wei, Tong; Cheng, Jie; Fan, Zhuangjun; Zhang, Milin

    2010-02-15

    Lamellar birnessite-type MnO{sub 2} materials were prepared by changing the pH of the initial reaction system via hydrothermal synthesis. The interlayer spacing of MnO{sub 2} with a layered structure increased gradually when the initial pH value varied from 12.43 to 2.81, while the MnO{sub 2}, composed of {alpha}-MnO{sub 2} and {gamma}-MnO{sub 2}, had a rod-like structure at pH 0.63. Electrochemical studies indicated that the specific capacitance of birnessite-type MnO{sub 2} was much higher than that of rod-like MnO{sub 2} at high discharge current densities due to the lamellar structure with fast intercalation/deintercalation of protons and high utilization of MnO{sub 2}. The initial specific capacitance of MnO{sub 2} prepared at pH 2.81 was 242.1 F g{sup -1} at 2 mA cm{sup -2} in 2 mol L{sup -1} (NH{sub 4}){sub 2}SO{sub 4} aqueous electrolyte. The capacitance increased by about 8.1% of initial capacitance after 200 cycles at a current density of 100 mA cm{sup -2}.

  11. In operando X-ray studies of the conversion reaction in Mn3O4...

    Office of Scientific and Technical Information (OSTI)

    of the conversion reaction in Mn3O4 lithium battery anodes Citation Details ... energy storage (including batteries and capacitors), hydrogen and fuel ...

  12. Phase stability of the SrMnO[subscript 3] hexagonal perovskite...

    Office of Scientific and Technical Information (OSTI)

    SrMnOsubscript 3 hexagonal perovskite system at high pressure and temperature Citation ... Country of Publication: United States Language: ENGLISH Word Cloud More Like This Full ...

  13. International Falls, MN Natural Gas Pipeline Imports From Canada (Dollars

    U.S. Energy Information Administration (EIA) Indexed Site

    per Thousand Cubic Feet) Dollars per Thousand Cubic Feet) International Falls, MN Natural Gas Pipeline Imports From Canada (Dollars per Thousand Cubic Feet) Decade Year-0 Year-1 Year-2 Year-3 Year-4 Year-5 Year-6 Year-7 Year-8 Year-9 1990's 1.71 2.03 2.00 2.33 2000's 2.77 4.85 3.01 -- -- 11.20 -- - = No Data Reported; -- = Not Applicable; NA = Not Available; W = Withheld to avoid disclosure of individual company data. Release Date: 08/31/2016 Next Release Date: 09/30/2016 Referring Pages:

  14. International Falls, MN Natural Gas Pipeline Imports From Canada (Million

    U.S. Energy Information Administration (EIA) Indexed Site

    Cubic Feet) Million Cubic Feet) International Falls, MN Natural Gas Pipeline Imports From Canada (Million Cubic Feet) Decade Year-0 Year-1 Year-2 Year-3 Year-4 Year-5 Year-6 Year-7 Year-8 Year-9 1990's 6,373 6,544 6,103 4,857 2000's 3,022 617 602 0 0 22 0 - = No Data Reported; -- = Not Applicable; NA = Not Available; W = Withheld to avoid disclosure of individual company data. Release Date: 08/31/2016 Next Release Date: 09/30/2016 Referring Pages: U.S.

  15. Electrochemical performance studies of MnO{sub 2} nanoflowers recovered from spent battery

    SciTech Connect (OSTI)

    Ali, Gomaa A.M.; Tan, Ling Ling; Jose, Rajan; Yusoff, Mashitah M.; Chong, Kwok Feng

    2014-12-15

    Highlights: MnO{sub 2} is recovered from spent zinccarbon batteries as nanoflowers structure. Recovered MnO{sub 2} nanoflowers show high specific capacitance. Recovered MnO{sub 2} nanoflowers show stable electrochemical cycling up to 900 cycles. Recovered MnO{sub 2} nanoflowers show low resistance in EIS data. - Abstract: The electrochemical performance of MnO{sub 2} nanoflowers recovered from spent household zinccarbon battery is studied by cyclic voltammetry, galvanostatic charge/discharge cycling and electrochemical impedance spectroscopy. MnO{sub 2} nanoflowers are recovered from spent zinccarbon battery by combination of solution leaching and electrowinning techniques. In an effort to utilize recovered MnO{sub 2} nanoflowers as energy storage supercapacitor, it is crucial to understand their structure and electrochemical performance. X-ray diffraction analysis confirms the recovery of MnO{sub 2} in birnessite phase, while electron microscopy analysis shows the MnO{sub 2} is recovered as 3D nanostructure with nanoflower morphology. The recovered MnO{sub 2} nanoflowers exhibit high specific capacitance (294 F g{sup ?1} at 10 mV s{sup ?1}; 208.5 F g{sup ?1} at 0.1 A g{sup ?1}) in 1 M Na{sub 2}SO{sub 4} electrolyte, with stable electrochemical cycling. Electrochemical data analysis reveal the great potential of MnO{sub 2} nanoflowers recovered from spent zinccarbon battery in the development of high performance energy storage supercapacitor system.

  16. Lattice Mn3+ Behaviors in Li4Ti5O12/LiNi0.5Mn1.5O4 Full Cells

    SciTech Connect (OSTI)

    Zheng, Jianming; Xiao, Jie; Nie, Zimin; Zhang, Jiguang

    2013-05-28

    High voltage spinels LiNi0.5Mn1.5O4 (LNMO) with different contents of residual Mn3+ ions have been evaluated in full cells using Li4Ti5O12 (LTO) as standard anode. Greatly improved cycling stability has been observed for all spinels in LTO-limited full cell, compared with those in LNMO-limited ones, while the underlying mechanisms are quite different. It has been discovered that the participation of active Mn3+ in the extended cycling and thus its observable contribution to Li+ diffusion kinetics depend on the limiting electrode and the sufficiency of Li+ ions. Potential Mn dissolution has also been discussed to identify the key factors that need to be considered to construct full cells employing high voltage spinel as the cathode.

  17. Magnetic and structural properties of Zn doped MnV{sub 2}O{sub 4}

    SciTech Connect (OSTI)

    Shahi, Prashant; Shukla, K. K.; Singh, Rahul; Chatterjee, Sandip; Das, A.; Ghosh, A. K.; Nigam, A. K.

    2014-04-24

    The magnetization, Neutron diffraction and X-ray diffraction of Zn doped MnV{sub 2}O{sub 4} as a function of temperature have been measured. It has been observed, with increase of Zn the non-linear orientation of Mn spins with the V spins will decrease which effectively decrease the structural transition temperature more rapidly than Curie Temperature.

  18. Spin correlations and electron transport in MnBi:Au films

    SciTech Connect (OSTI)

    Kharel, P.; Skomski, R.; Sellmyer, D. J.

    2011-04-01

    The structural, magnetic, and electron transport properties of Mn{sub 55-x}Au{sub x}Bi{sub 45} (x = 0, 4.5) thin films prepared by magnetron sputtering have been investigated. The magnetization of the MnBi films decreases and the coercivity increases due to Au doping. The temperature dependence of resistivity between 2 to 300 K shows that the films are metallic but the 4.5% Au-doped film shows a Kondo behavior with resistance minimum at 10.2 K. The magnetoresistance is anisotropic and the positive transverse magnetoresistance is significantly enhanced (16.3% at 70 kOe) by Au doping. We interpret these data in terms of a model in which Au atoms preferentially substitute for Mn atoms on the Mn lattice, and some Mn atoms are displaced to interstitial sites in the NiAs structure. These interstitial Mn atoms are coupled antiferromagnetically to the Mn atoms on the original Mn lattice leading to the large decrease in magnetization, Kondo effect, and the positive magnetoresistance.

  19. Impedance studies of the thin film LiMn2O4/electrolyteinterface

    SciTech Connect (OSTI)

    Striebel, Kathryn A.; Sakai, E.; Cairns, Elton J.

    2001-04-07

    Room-temperature impedance measurements of a thin-film LiMn2O4/LiPF6-EC-DMC interface have been used to identify the spontaneous formation Li2Mn2O4 at the interface at room temperature at voltages of 3.7 and higher. The impedance of the LiMn2O4 films exhibited two time constants: at about 14 kHz and 60 to 200 Hz. The high frequency loop is dependent on film morphology and was attributed to the substrate/oxide interface. The low frequency behavior was dependent on both state-of-charge (SOC) and time at a given SOC. At full charge the impedance in this electrolyte was stable at room temperature over several days. At high lithium contents, film OCV and impedance tended to grow logarithmically with time, with lower rates for lower Mn3+ content in the film. The increased impedance was removed by oxidation of the film to 4.5V vs. Li/Li+. The observations are consistent with a reversible disproportionation of part of the LiMn2O4 into Li2Mn2O4 and a lithium-deficient spinel. With extended constant current cycling part of the Li2Mn2O4 degrades to the Mn2O3 and the process is no longer reversible.

  20. Room temperature spin-polarizations of Mn-based antiferromagnetic nanoelectrodes

    SciTech Connect (OSTI)

    Yamada, Toyo Kazu; Vazquez de Parga, Amadeo L.

    2014-11-03

    Antiferromagnets produce no stray field, and therefore, a tip electrode made of antiferromagnetic material has been considered to be the most suitable choice to measure such as magnetoresistance (MR) through single isolated magnetic nanoparticles, molecules, and ultrathin films. Spin polarizations (P) of antiferromagnetic 3-nm, 6-nm, and annealed 3-nm Mn films grown on W tips with a bcc(110) apex as well as bulk-NiMn tips were obtained at 300?K by measuring MR in ultrahigh vacuum by means of spin-polarized scanning tunneling microscopy using a layerwise antiferromagnetically stacking bct-Mn(001) film electrode. The Mn-coated tips with coverages of 3 and 6?nm exhibited P values of 1??1% and 3??2%, respectively, which tips likely contain ?- or strained Mn. With a thermal assist, the crystalline quality and the magnetic stability of the film could increase. The annealed tip exhibited P?=?9??2%. The bulk-NiMn tips exhibit spin polarizations of 0 or 6??2% probably depending on the chemical species (Mn or Ni) present at the apex of the tip. Fe-coated W tips were used to estimate the bct-Mn(001) film spin polarization.

  1. Site Determination and Magnetism of Mn Doping in Protein Encapsulated Iron Oxide Nanoparticles

    SciTech Connect (OSTI)

    Pool, V.; Klem, M.; Jolley, J.; Arenholz, E.A.; Douglas, T.; Young, M.; Idzerda, Y.U.

    2010-01-11

    Soft-X-ray absorption spectroscopy, soft-X-ray magnetic circular dichroism, and alternating current magnetic susceptibility were performed on 6.7 nm iron oxide nanoparticles doped with (5-33%) Mn grown inside the horse-spleen ferritin protein cages and compared to similarly protein encapsulated pure Fe-oxide and Mn-oxide nanoparticles to determine the site of the Mn dopant and to quantify the magnetic behavior with varying Mn concentration. The Mn dopant is shown to substitute preferentially as Mn{sup +2} and prefers the octahedral site in the defected spinel structure. The Mn multiplet structure for the nanoparticles is simpler than for the bulk standards, suggesting that the nanoparticle lattices are relaxed from the distortions present in the bulk. Addition of Mn is found to alter the host Fe-oxide lattice from a defected ferrimagnetic spinel structure similar to {gamma}-Fe{sub 2}O{sub 3} to an non-ferromagnetic spinel structure with a local Fe environment similar to Fe{sub 3}O{sub 4}.

  2. Electric-Field Modulation of Curie Temperature in (Ga, Mn)As Field-Effect Transistor Structures with Varying Channel Thickness and Mn Compositions

    SciTech Connect (OSTI)

    Nishitani, Y.; Endo, M.; Chiba, D.; Matsukura, F.; Ohno, H.

    2010-01-04

    We have investigated the change of T{sub C} of ferromagnetic semiconductor (Ga, Mn)As by changing hole concentration p. The field effect transistor structure was utilized to change p. The relation T{sub C}propor top{sup 0.2} is obtained for three samples, despite the difference of their Mn composition and thickness, indicating that the relation holds over 2 decades of p.

  3. K and Mn co-doped BaCd{sub 2}As{sub 2}: A hexagonal structured...

    Office of Scientific and Technical Information (OSTI)

    K and Mn co-doped BaCdsub 2Assub 2: A hexagonal structured bulk diluted magnetic semiconductor with large magnetoresistance Citation Details In-Document Search Title: K and Mn ...

  4. Scanning tunneling microscopy reveals LiMnAs is a room temperature anti-ferromagnetic semiconductor

    SciTech Connect (OSTI)

    Wijnheijmer, A. P.; Koenraad, P. M.; Marti, X.; Holy, V.; Cukr, M.; Novak, V.; Jungwirth, T.

    2012-03-12

    We performed scanning tunneling microscopy and spectroscopy on a LiMnAs(001) thin film epitaxially grown on an InAs(001) substrate by molecular beam epitaxy. While the in situ cleavage exposed only the InAs(110) non-polar planes, the cleavage continued into the LiMnAs thin layer across several facets. We combined both topography and current mappings to confirm that the facets correspond to LiMnAs. By spectroscopy we show that LiMnAs has a band gap. The band gap evidenced in this study, combined with the known Neel temperature well above room temperature, confirms that LiMnAs is a promising candidate for exploring the concepts of high temperature semiconductor spintronics based on antiferromagnets.

  5. Magnetic properties and photoabsorption of the Mn-doped CeO{sub 2} nanorods

    SciTech Connect (OSTI)

    Xia, Chuanhui; Science College of Chongqing Jiaotong University, Chongqing 400074 ; Hu, Chenguo; Chen, Peng; Wan, Buyong; He, Xiaoshan; Tian, Yongshu; Chongqing Communication College, Chongqing 400035

    2010-07-15

    Mn-doped CeO{sub 2} nanorods have been prepared from CeO{sub 2} particles through a facile composite-hydroxide-mediated (CHM) approach. The analysis from X-ray photoelectron spectroscopy indicates that the manganese doped in CeO{sub 2} exists as Mn{sup 2+}. The magnetic measurement of the Mn-doped CeO{sub 2} nanorods exhibits an enhanced ferromagnetic property at room temperature with a remanence magnetization (Mr) of 1.36 x 10{sup -3} emu/g and coercivity (Hc) of 22 Oe. Comparative UV-visible spectra reveal the shift of the absorption peak of the CeO{sub 2} from ultraviolet region to visible light region after being doped with Mn. The room temperature ferromagnetic properties and light absorption of the Mn-doped CeO{sub 2} nanorods would have potential applications in photocatalysis and building of photovoltaic devices.

  6. Giant atomic displacement at a magnetic phase transition in metastable Mn3O4

    SciTech Connect (OSTI)

    Hirai, Shigeto; Moreira Dos Santos, Antonio F; Shapiro, Max C; Molaison, Jamie J; Pradhan, Neelam; Guthrie, Malcolm; Tulk, Christopher A; Fisher, Ian R; Mao, Wendy

    2013-01-01

    We present x-ray, neutron scattering, and heat capacity data that reveal a coupled first-order magnetic and structural phase transition of the metastable mixed-valence postspinel compound Mn3O4 at 210 K. Powder neutron diffraction measurements reveal a magnetic structure in which Mn3+ spins align antiferromagnetically along the edge-sharing a axis, with a magnetic propagation vector k = [1/2,0,0]. In contrast, the Mn2+ spins, which are geometrically frustrated, do not order until a much lower temperature. Although the Mn2+ spins do not directly participate in the magnetic phase transition at 210 K, structural refinements reveal a large atomic shift at this phase transition, corresponding to a physical motion of approximately 0.25 angstrom, even though the crystal symmetry remains unchanged. This "giant" response is due to the coupled effect of built-in strain in the metastable postspinel structure with the orbital realignment of the Mn3+ ion.

  7. Ferromagnetic (Ga,Mn)As nanostructures for spintronic applications

    SciTech Connect (OSTI)

    Wosinski, Tadeusz; Andrearczyk, Tomasz; Figielski, Tadeusz; Makosa, Andrzej; Wrobel, Jerzy; Sadowski, Janusz

    2013-12-04

    Magneto-resistive, cross-like nanostructures have been designed and fabricated by electron-beam lithography patterning and chemical etching from thin epitaxial layers of the ferromagnetic semiconductor (Ga,Mn)As. The nanostructures, composed of two perpendicular nanostripes crossing in the middle of their length, represent four-terminal devices, in which an electric current can be driven through any of the two nanostripes. In these devices, a novel magneto-resistive memory effect, related to a rearrangement of magnetic domain walls in the central part of the device, has been demonstrated. It consists in that the zero-field resistance of a nanostripe depends on the direction of previously applied magnetic field. The nanostructures can thus work as two-state devices providing basic elements of nonvolatile memory cells.

  8. Impedance analysis of MnCoCuO NTC ceramic

    SciTech Connect (OSTI)

    Song, S.G. . E-mail: song-ph0@wpmail.paisley.ac.uk; Ling, Z.; Placido, F.

    2005-07-12

    Impedance spectroscopy is often used to analyse the electrical properties of ceramic materials having high-resistive grain boundaries, such as ZnO and SrTiO{sub 3}. Fewer attempts have been made at using this technique for the analysis of inhomogeneous electronic ceramics consisting of grains with differing composition, such as those occurring in negative temperature coefficient (NTC) thermistors. In this study, we have attempted to adopt ac impedance spectroscopy together with other techniques to analyse an NTC thermistor ceramic material. An Mn, Co and Cu multielements transition metal oxide (MnCoCuO) ceramic was prepared by using homogeneous precipitation employing oxalic acid. This material displayed a typical NTC effect, showing an electrical resistance decrease with temperature when dc electrical measurement was performed. The ac impedance spectroscopy analysis showed that there were two peaks in impedance and conductance versus frequency plot. By using an alternative representation of impedance spectra Z'/f versus Z', three distinct relaxation frequency ranges were identified. They are believed to originate, respectively, from the electrode, phase 1 (rich-Cu phase) and phase 2 (poor-Cu phase) grains existing in this ceramic. SEM observation and EDX analysis clearly showed existence of two distinct phase grains. The resistance values were derived from phases 1 and 2 grains based on ac impedance data. The sum of the resistance values was in good agreement with that from dc measurement in the temperature range of 30-95 deg. C. The material constant, B, for the two phases was also calculated, giving 3100 and 3600 K for phases 1 and 2, respectively.

  9. Ab initio study of Fe{sub 2}MnZ (Al, Si, Ge) Heusler alloy using GGA approximation

    SciTech Connect (OSTI)

    Jain, Vivek Kumar Jain, Vishal Lakshmi, N. Venugopalan, K.

    2014-04-24

    Density functional theory based on FP-LAPW method used to investigate the electronic structure of Fe{sub 2}MnZ, shows that the total spin magnetic moment shows a trend consistent with the Slater–Pauling curve. The Fe and Mn magnetic moment depend on choice of Z element although the magnetic moment of Z element is negative and less than 0.1 μ{sub B}. Spin polarization calculations evidence 100% spin polarization for Fe{sub 2}MnSi. Fe{sub 2}MnAl and Fe{sub 2}MnGe show metallic behavior with 93%, 98% spin polarization.

  10. U.S. Natural Gas Pipeline Imports by Point of Entry

    U.S. Energy Information Administration (EIA) Indexed Site

    Marysville, MI 5,694 9,946 8,099 2,337 4,650 1,961 1996-2015 St. Clair, MI 5,591 5,228 3,531 6,019 16,409 9,024 1996-2015 International Falls, MN 1996-2006 Noyes, MN 447,079 ...

  11. Recent progress of magnetocaloric effect and magnetic refrigerant materials of Mn compounds (invited)

    SciTech Connect (OSTI)

    Wada, H. Takahara, T.; Katagiri, K.; Ohnishi, T.; Soejima, K.; Yamashita, K.

    2015-05-07

    Magnetocaloric and related properties of Ru and Ni substituted (MnFe){sub 2}(PSi) are presented. It is found that Ru and Ni are effective doping elements to reduce the thermal hysteresis of (MnFe){sub 2}(PSi). The origin of the thermal hysteresis is discussed on the basis of a thermodynamic model. It is shown that the elastic energy is responsible for the thermal hysteresis. We also show recent developments of the production process of Mn compounds in an industrial scale.

  12. Quantum Anomalous Hall Effect in Hg_1-yMn_yTe Quantum Wells

    SciTech Connect (OSTI)

    Liu, Chao-Xing; Qi, Xiao-Liang; Dai, Xi; Fang, Zhong; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

    2010-03-19

    The quantum Hall effect is usually observed when the two-dimensional electron gas is subjected to an external magnetic field, so that their quantum states form Landau levels. In this work we predict that a new phenomenon, the quantum anomalous Hall effect, can be realized in Hg{sub 1-y}Mn{sub y}Te quantum wells, without the external magnetic field and the associated Landau levels. This effect arises purely from the spin polarization of the Mn atoms, and the quantized Hall conductance is predicted for a range of quantum well thickness and the concentration of the Mn atoms. This effect enables dissipationless charge current in spintronics devices.

  13. Unoccupied electronic structure of Ni2MnGa ferromagnetic shape memory alloy

    SciTech Connect (OSTI)

    Maniraj, M.; D?Souza, S. W.; Rai, Abhishek; Schlagel, D. L.; Lograsso, T. A.; Chakrabarti, Aparna; Barman, S. R.

    2015-08-20

    Momentum resolved inverse photoemission spectroscopy measurements show that the dispersion of the unoccupied bands of Ni2MnGa is significant in the austenite phase. Furthermore, in the martensite phase, it is markedly reduced, which is possibly related to the structural transition to an incommensurate modulated state in the martensite phase. Finally, based on the first principle calculations of the electronic structure of NiMnGa, we show that the modification of the spectral shape with surface composition is related to change in the hybridization between the Mn 3d and Ni 3d-like states that dominate the unoccupied conduction band.

  14. Role of Cu-Ion Doping in Cu-α-MnO2 Nanowire Electrocatalysts for the Oxygen Reduction Reaction

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Davis, Danae J.; Lambert, Timothy N.; Vigil, Julian A.; Rodriguez, Mark A.; Brumbach, Michael T.; Coker, Eric N.; Limmer, Steven J.

    2014-07-09

    The role of Cu-ion doping in α-MnO2 electrocatalysts for the oxygen reduction reaction in alkaline electrolyte was investigated. Copper doped α-MnO2 nanowires (Cu-α-MnO2) were prepared with varying amounts of Cu2+ using a solvothermal method. The electrocatalytic dataindicates that Cu-α-MnO2 nanowires have higher terminal current densities, enhanced kinetic rate constants, and improved charge transfer resistances that trend with Cu-content, exceeding values attained by α-MnO2 alone. The observed improvement in catalytic behavior correlates with an increase in Mn3+ content for the Cu-α-MnO2 nanowires. The Mn3+/Mn4+ couple is themediator for the rate-limiting redox driven O2-/OH- exchange. It is proposed that O2 adsorbs viaanmore » axial site (the eg orbital on the Mn3+ d4 ion) at the surface, or at edge defects, of the nanowireand that the increase in covalent nature of the nanowire with Cu-ion doping leads to stabilization of O2 adsorbates and faster rates of reduction. This work is applicable to other manganese oxide electrocatalysts and shows for the first time there is a correlation for manganese oxides between electrocatalytic activity for the ORR in alkaline electrolyte and an increase in Mn3+ character of the oxide.« less

  15. Unique light-induced degradation in yellow-emitting K₂SiF₆:Mn²⁺ phosphor

    SciTech Connect (OSTI)

    Oyama, Takuya; Adachi, Sadao

    2014-10-07

    Photo-induced luminescence intensity degradation in yellow-emitting K₂SiF₆:Mn²⁺ phosphor is studied using x-ray diffraction measurement, photoluminescence (PL) analysis, PL excitation (PLE) spectroscopy, PL decay analysis, and electron spin resonance (ESR) measurement. The yellow-emitting K₂SiF₆:Mn²⁺ phosphor exhibits remarkable degradation in the PL intensity under Xe lamp exposure. Coherent laser irradiation also induces degradation and its degree is in the order of He–Cd (λ = 325 nm) > Ar⁺ (488 nm) > He–Ne laser (632.8 nm). The degradation mechanism is proposed to be due to change in the valence state of manganese ions from Mn²⁺ to Mn³⁺ by the photooxidation (Mn²⁺ → Mn³⁺) or disproportionation reaction (2Mn²⁺ → Mn⁺ + Mn³⁺). The ESR measurement confirms the decreased Mn²⁺ spin density in the sample exposed with Xe lamp. The PLE spectrum suggests that the excitation of Mn³⁺ ions occurs through energy transfer upon absorption of exciting radiation by the Mn²⁺ ions. Thermal annealing of the degraded samples at ≥200 °C causes a blueshift in the PL emission band with an appearance of the Mn⁴⁺-related sharp red emission lines.

  16. Planar Hall effect in Y{sub 3}Fe{sub 5}O{sub 12}/IrMn films

    SciTech Connect (OSTI)

    Zhang, X. Zou, L. K.

    2014-12-29

    The planar Hall effect of IrMn on an yttrium iron garnet (YIG = Y{sub 3}Fe{sub 5}O{sub 12}) was measured in the magnetic field rotating in the film plane. The magnetic field angular dependence of planar Hall resistance (PHR) was observed in YIG/IrMn bilayer at different temperatures, while the Gd{sub 3}Ga{sub 5}O{sub 12}/IrMn film shows constant PHR for different magnetic field angles at both 10 K and 300 K. This provides evidence that IrMn has interfacial spins which can be led by ferrimagnetic layer in YIG/IrMn structure. A hysteresis can be observed in PHR-magnetic field angle loop of YIG/IrMn film at 10 K, indicative of the irreversible switching of IrMn interfacial spins at low temperature.

  17. First-principles study of spin-transfer torque in Co{sub 2}MnSi/Al/Co{sub 2}MnSi spin-valve

    SciTech Connect (OSTI)

    Tang, Ling Yang, Zejin

    2013-11-21

    The spin-transfer torque (STT) in Co{sub 2}MnSi(CMS)/Al/Co{sub 2}MnSi spin-valve system with and without interfacial disorder is studied by a first-principles noncollinear wave-function-matching method. It is shown that in the case of clean interface the angular dependence of STT for CoCo/Al (the asymmetry parameter Λ≈4.5) is more skewed than that for MnSi/Al (Λ≈2.9), which suggests the clean CoCo/Al architecture is much more efficient for the application on radio frequency oscillation. We also find that even with interfacial disorder the spin-valve of half-metallic CMS still has a relatively large parameter Λ compared to that of conventional ferromagnet. In addition, for clean interface the in-plane torkance of MnSi/Al is about twice as large as that of CoCo/Al. However, as long as the degree of interfacial disorder is sufficiently large, the CoCo/Al and MnSi/Al will show approximately the same magnitude of in-plane torkance. Furthermore, our results demonstrate that CMS/Al/CMS system has very high efficiency of STT to switch the magnetic layer of spin-valve.

  18. Niagara Falls, NY Natural Gas Imports by Pipeline from Canada

    Annual Energy Outlook [U.S. Energy Information Administration (EIA)]

    640,119 434,526 324,474 278,422 233,453 200,394 1982-2014 Import Price 4.67 5.43 4.96 3.83 5.59 8.60 1989-2014 Export Volume 0 0 38,783 68,843 184,071 201,691 1982-2014 Export Price -- -- 4.69 3.61 4.29 5.56 199

    223,532 202,549 188,208 183,548 185,119 196,365 1990-2016 Base Gas 114,992 114,956 114,913 114,853 114,603 114,779 1990-2016 Working Gas 108,540 87,594 73,296 68,695 70,516 81,586 1990-2016 Net Withdrawals 2,020 21,931 14,573 4,660 -1,571 -11,246 1990-2016 Injections 4,390 351 2,066

  19. DOE - Office of Legacy Management -- Niagara Falls Storage Site...

    Office of Legacy Management (LM)

    of Engineers but will eventually transfer to the U.S. Department of Energy Office of Legacy Management. Assessment of Historical Knolls Atomic Power Laboratory Waste Storage...

  20. MHK Projects/Niagara Community 2 | Open Energy Information

    Open Energy Info (EERE)

    Overseeing Organization ECOsponsible Project Licensing FERC License Docket Number P-13840 Environmental Monitoring and Mitigation Efforts See Tethys << Return to the MHK database...

  1. MHK Projects/Niagara Community | Open Energy Information

    Open Energy Info (EERE)

    Overseeing Organization ECOsponsible Project Licensing FERC License Docket Number P-13839 Environmental Monitoring and Mitigation Efforts See Tethys << Return to the MHK database...

  2. DOE - Office of Legacy Management -- Niagara Falls Vicinity Properties...

    Office of Legacy Management (LM)

    This site is currently managed by the U.S. Army Corps of Engineers but will eventually transfer to the U.S. Department of Energy Office of Legacy Management. Assessment of ...

  3. DOE - Office of Legacy Management -- Niagara Falls Storage Site...

    Office of Legacy Management (LM)

    This site is currently managed by the U.S. Army Corps of Engineers but will eventually transfer to the U.S. Department of Energy Office of Legacy Management. Assessment of ...

  4. Evaluation of Final Radiological Conditions at Areas of the Niagara...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Paper presented at the Waste Management 2012 Conference. February 26 through March 1, 2012, Phoenix, Arizona. Christopher Clayton, Vijendra Kothari, and Ken Starr, U.S. Department ...

  5. Niagara Falls, NY Natural Gas Exports to Canada

    Gasoline and Diesel Fuel Update (EIA)

    3a . January Monthly Peak Hour Demand, Actual by North American Electric Reliability Corporation Region, 2005 through 2009 (Megawatts) Texas Power Grid Western Power Grid Peak Hour Demand (MW) Peak Hour Demand (MW) Peak Hour Demand (MW) Peak Hour Demand (MW) Peak Hour Demand (MW) Peak Hour Demand (MW) Peak Hour Demand (MW) Peak Hour Demand (MW) Peak Hour Demand (MW) 2005 613,416 41,247 32,236 47,041 154,200 166,190 29,072 40,966 102,464 2006 563,711 34,464 37,056 43,661 149,252 134,239 26,864

  6. Niagara Falls, NY Natural Gas Imports by Pipeline from Canada

    Gasoline and Diesel Fuel Update (EIA)

    88,983 32,770 3,159 1,650 2,957 2,539 1996-2015 Pipeline Prices 5.43 4.68 3.22 4.04 5.08 3.2

  7. Spectroscopic properties of (PVA+ZnO):Mn{sup 2+} polymer films

    SciTech Connect (OSTI)

    Rani, Ch.; Raju, D. Siva; Bindu, S. Hima; Krishna, J. Suresh; Raju, Ch. Linga

    2015-05-15

    Electron Paramagnetic Resonance (EPR), optical absorption and infrared spectral studies have been carried out on Mn{sup 2+} ions doped in poly(vinyl alcohol) complexed with zinc oxide polymer films prepared by solution cast technique. The EPR spectra of 1 mol% Mn{sup 2+} ions doped polymer complex (PVA+ZnO) at room temperature exhibit sextet hyperfine structure (hfs), centered at 2.01. The spin-Hamiltonian parameter values indicate that the ground state of Mn{sup 2+} ion in d{sup 5} and the site symmetry around Mn{sup 2+} ions in tetragonally distorted octa hedral site. The optical absorption spectra exhibits two bands centered at 275nm at 437nm. The FTIR spectrum exhibits bands characteristic of stretching and banding vibrations of O-H, C-H and C=C groups.

  8. Effect of Mn substitution on the transport properties of co-sputtered...

    Office of Scientific and Technical Information (OSTI)

    on the transport properties of co-sputtered Fesub 3-xMnsub xSi epilayers Citation Details In-Document Search Title: Effect of Mn substitution on the transport properties of ...

  9. X-Ray Spectroscopy of the Mn(4) Ca Cluster in the Water-Oxidation...

    Office of Scientific and Technical Information (OSTI)

    Ca Cluster in the Water-Oxidation Complex of Photosystem II Citation Details In-Document Search Title: X-Ray Spectroscopy of the Mn(4) Ca Cluster in the Water-Oxidation Complex ...

  10. In-situ Electrical Conductivity of LixMnO2 Nanowires as a Function...

    Office of Scientific and Technical Information (OSTI)

    of LixMnO2 Nanowires as a Function of "x" and Size Authors: Le, Mya ; Liu, Yu ; Wang, Hui ; Dutta, Rajen ; Yan, Wenbo ; Hemminger, John C ; Wu, Ruqian ; Penner, Reginald...

  11. File:USDA-CE-Production-GIFmaps-MN.pdf | Open Energy Information

    Open Energy Info (EERE)

    MN.pdf Jump to: navigation, search File File history File usage Minnesota Ethanol Plant Locations Size of this preview: 776 600 pixels. Full resolution (1,650 1,275...

  12. Unoccupied electronic structure of Ni2MnGa ferromagnetic shape...

    Office of Scientific and Technical Information (OSTI)

    shape memory alloy This content will become publicly available on August 20, 2016 Prev Next Title: Unoccupied electronic structure of Ni2MnGa ferromagnetic shape memory alloy ...

  13. Microstructure and Mechanical Properties of Two-Phase Fe30Ni20Mn20Al30...

    Office of Scientific and Technical Information (OSTI)

    Title: Microstructure and Mechanical Properties of Two-Phase Fe30Ni20Mn20Al30 Alloy Authors: Wu, Xiaolan 1 ; Baker, Ian 1 ; Wu, H 1 ; Miller, Michael K 2 ; More, Karren ...

  14. Magnetocaloric effect of Pr2Fe17-x Mn x alloys (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Search Results Journal Article: Magnetocaloric effect of Pr2Fe17-x Mn x ... OSTI Identifier: 1221829 Report Number(s): IS-J 8426 Journal ID: ISSN 1001-0521; PII: 134 ...

  15. Modeling and Characterization of the Magnetocaloric Effect in Ni2MnGa Materials

    SciTech Connect (OSTI)

    Nicholson, Don M; Odbadrakh, Khorgolkhuu; Rios, Orlando; Hodges, Jason P; Ludtka, Gerard Michael; Porter, Wallace D; Sefat, A. S.; Rusanu, Aurelian; Evans III, Boyd Mccutchen

    2012-01-01

    Magnetic shape memory alloys have great promise as magneto-caloric effect refrigerant materials due to their combined magnetic and structural transitions. Computational and experimental research is reported on the Ni2MnGa material system. The magnetic states of this system have been explored using the Wang-Landau statistical approach in conjunction with the Locally Self-consistent Multiple-Scattering (LSMS) method to explore the magnetic states responsible for the magnet-caloric effect in this material. The effects of alloying agents on the transition temperatures of the Ni2MnGa alloy were investigated using differential scanning calorimetry (DSC) and superconducting quantum interference device (SQUID). Neutron scattering experiments were performed to observe the structural and magnetic phase transformations at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) on alloys of Ni-Mn-Ga and Ni-Mn-Ga-Cu-Fe. Data from the observations are discussed in comparison with the computational studies.

  16. Pressure-Induced Metallization of the Mott Insulator MnO (Journal...

    Office of Scientific and Technical Information (OSTI)

    Pressure-Induced Metallization of the Mott Insulator MnO Citation ... Publication Date: 2004-01-12 OSTI Identifier: 15013737 Report Number(s): UCRL-JRNL-201933 Journal ID: ISSN ...

  17. Electrochemical Performances of LiMnPO4 Synthesized from Non...

    Office of Scientific and Technical Information (OSTI)

    Li1.1MnPO4 exhibits the most stable cycling ability probably because of the existence of a trace amount of Li3PO4 impurity that functions as a solid-state electrolyte on...

  18. Synthesis and characterization of MnPS{sub 3} for hydrogen sorption

    SciTech Connect (OSTI)

    Ismail, N.; Temerk, Y.M.; El-Meligi, A.A.; Badr, M.A.; Madian, M.

    2010-05-15

    Single phase MnPS{sub 3} powder was prepared by solid state reaction between Mn, S and P carried out at 650 deg. C in evacuated silica tube. The structure, morphology and sorption characteristics of the prepared solid were investigated. The results revealed that the obtained MnPS{sub 3} compound was capable of adsorbing 3.5 wt% hydrogen at -193 deg. C and a pressure of 30 bar. Little amount of hydrogen (0.07 wt%) was adsorbed at room temperature. The hydrogen adsorption/desorption cycles at various temperatures did not result in irreversible chemical structural changes of the MnPS{sub 3} compound, but the microstructure after hydrogen cycling diminished and became finer. - Graphical abstract: Atomic building of MPS{sub 3}

  19. Understanding the Structural and Electronic Evolution of Li2MnO3 During

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Electron Irradiation Via Electron Microscopy - Joint Center for Energy Storage Research November 17, 2014, Research Highlights Understanding the Structural and Electronic Evolution of Li2MnO3 During Electron Irradiation Via Electron Microscopy In-situ electron beam irradiation induces localized pockets of damage (a) and (b) characterized by the Mn atoms migrating to occupy Li sites, as shown in the annular bright field image of (c). This effect is clearly visible in an intensity line profile

  20. The role of C and Mn at the austenite/pearlite reaction front during non-steady-state pearlite growth in a Fe-C-Mn steel

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aranda, M. M.; Rementeria, R.; Poplawsky, Jonathan D.; Urones-Garrote, E.; Capdevila, Carlos

    2015-04-18

    The role of C and Mn during the growth of pearlite under non-steady state conditions is analyzed by comparing the phase compositions of austenite, ferrite and cementite (γ+α+θ) through the use of transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and atom probe tomography (APT) measurements across the austenite/pearlite interface. Furthermore, a local Mn enrichment and C depletion at the austenite/pearlite interface has been measured, which causes a change in the driving force with time during divergent pearlite growth.

  1. The structure of the Caenorhabditis elegans manganese superoxide dismutase MnSOD-3-azide complex

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hunter, Gary J.; Trinh, Chi H.; Bonetta, Rosalin; Stewart, Emma E.; Cabelli, Diane E.; Hunter, Therese

    2015-08-27

    C. elegans MnSOD-3 has been implicated in the longevity pathway and its mechanism of catalysis is relevant to the aging process and carcinogenesis. The structures of MnSOD-3 provide unique crystallographic evidence of a dynamic region of the tetrameric interface (residues 41–54). We have determined the structure of the MnSOD-3-azide complex to 1.77-Å resolution. The analysis of this complex shows that the substrate analog, azide, binds end-on to the manganese center as a sixth ligand and that it ligates directly to a third and new solvent molecule also positioned within interacting distance to the His30 and Tyr34 residues of the substratemore » access funnel. This is the first structure of a eukaryotic MnSOD-azide complex that demonstrates the extended, uninterrupted hydrogen-bonded network that forms a proton relay incorporating three outer sphere solvent molecules, the substrate analog, the gateway residues, Gln142, and the solvent ligand. This configuration supports the formation and release of the hydrogen peroxide product in agreement with the 5-6-5 catalytic mechanism for MnSOD. The high product dissociation constant k₄ of MnSOD-3 reflects low product inhibition making this enzyme efficient even at high levels of superoxide.« less

  2. Hydrothermal synthesis of Mn vanadate nanosheets and visible-light photocatalytic performance for the degradation of methyl blue

    SciTech Connect (OSTI)

    Pei, L.Z. Xie, Y.K.; Pei, Y.Q.; Jiang, Y.X.; Yu, H.Y.; Cai, Z.Y.

    2013-07-15

    Graphical abstract: - Highlights: Mn vanadate nanosheets have been synthesized by simple hydrothermal process. The formation of Mn vanadate nanosheets can be controlled by growth conditions. Mn vanadate nanosheets exhibit good photocatalytic activities for methyl blue. - Abstract: Mn vanadate nanosheets have been synthesized via a facile hydrothermal route using ammonium metavanadate and Mn acetate as the raw materials, polyvinyl pyrrolidone (PVP) as the surfactant. X-ray diffraction (XRD) shows that the Mn vanadate nanosheets are composed of monoclinic MnV{sub 2}O{sub 6} phase. Scanning electron microscopy (SEM) observation indicates that the nanosheets have the average thickness of about 50 nm, length of 210 ?m and width of 800 nm to 2 ?m. The growth process of the Mn vanadate nanosheets has also been discussed based on the analysis of the roles of the growth conditions on the formation of the Mn vanadate nanosheets. The nanosheets show good photocatalytic activities for the degradation of methylene blue (MB) under visible light irradiation. About 72.96% MB can be degraded after visible light irradiation for 1 h over 10 mg Mn vanadate nanosheets in 10 mL MB solution with the concentration of 10 mg L{sup ?1}.

  3. Inverse magnetocaloric effect in Mn{sub 2}NiGa and Mn{sub 1.75}Ni{sub 1.25}Ga magnetic shape memory alloys

    SciTech Connect (OSTI)

    Singh, Sanjay Barman, S. R.; Esakki Muthu, S.; Arumugam, S.; Senyshyn, A.; Rajput, P.; Suard, E.

    2014-02-03

    Inverse magnetocaloric effect is demonstrated in Mn{sub 2}NiGa and Mn{sub 1.75}Ni{sub 1.25}Ga magnetic shape memory alloys. The entropy change at the martensite transition is larger in Mn{sub 1.75}Ni{sub 1.25}Ga, and it increases linearly with magnetic field in both the specimens. Existence of inverse magnetocaloric effect is consistent with the observation that magnetization in the martensite phase is smaller than the austenite phase. Although the Mn content is smaller in Mn{sub 1.75}Ni{sub 1.25}Ga, from neutron diffraction, we show that the origin of inverse magnetocaloric effect is the antiferromagnetic interaction between the Mn atoms occupying inequivalent sites.

  4. The prominent role of oxygen in the multiferroicity of DyMnO3 and TbMnO3: a resonant soft x-ray scattering spectroscopy study

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    S. W. Huang; Lee, J. M.; Jeng, H. -T.; Shao, Y.; Wray, L. A.; Chen, J. M.; Qiao, R.; Yang, W. L.; Cao, Y.; Lin, J. -Y.; et al

    2016-07-21

    Oxygen is known to play an important role in the multiferroicity of rare earth manganites; however, how this role changes with rare earth elements is still not fully understood. To address this question, we have used resonant soft x-ray scattering spectroscopy to study the F-type (0; ; 0) diffraction peak from the antiferromagnetic order in DyMnO3 and TbMnO3. We focus on the measurements at O K-edge of these two manganites, supplemented by the results at Mn L2- and Dy M5-edge of DyMnO3. We show that the electronic states of di erent elements are coupled more strongly in DyMnO3 than inmore » TbMnO3, presumably due to the stronger lattice distortion and the tendency to develop E-type antiferromagnetism in the ferroelectric state that promote the orbital hybridization. We also show that the anomaly in the correlation length of (0; ; 0) peak in DyMnO3 signifies the exchange interaction between Mn and rare earth spins, which is absent in TbMnO3. Our findings reveal the prominent role of oxygen orbitals in the multiferroicity of rare earth manganites and the distinct energetics between them.« less

  5. Electron scattering mechanisms in Cu-Mn films for interconnect applications

    SciTech Connect (OSTI)

    Misjk, F.; Nagy, K. H.; Radnczi, G.; Lobotka, P.

    2014-08-28

    Electrical properties and corresponding structural features of Cu-Mn alloy films with potential application as barrier and interconnect layers were studied. Cu-Mn films were deposited by DC magnetron sputtering at room temperature on SiO{sub 2} substrates. Electrical resistivity measurements were made as a function of film composition and temperature. The specific resistivity varies linearly with the Mn content showing a maximum of 205???cm at 80 at. % Mn. The temperature coefficient of resistance (TCR) of all alloy films is low, showing non-metallic conductivity for most compositions. Also a minimum TCR has been observed in the 4080 at. % Mn range which was attributed to a magnetic transformation around 200300?K. Electrical resistivity measurements are correlated with the film structure revealed by transmission electron microscopy to clarify the phase regions throughout the composition range. In the 2040 at. % and 7080 at. % Mn ranges, two-phase structures were identified, where Cu- or Mn-rich solid solution grains were surrounded by a thin amorphous covering layer. Based on the revealed phase regions and morphologies electron scattering mechanisms in the system were evaluated by combining the Matthiessen's rule and the Mayadas-Schatzkes theory. Grain boundary reflectivity coefficients (r?=?0.60.8) were calculated from fitting the model to the measurements. The proposed model indicates that, in a binary system, the special arrangement of the two phases results in new scattering mechanisms. The results are of value in optimizing the various parameters needed to produce a suitable barrier layer.

  6. Synthesis of spherical LiMnPO{sub 4}/C composite microparticles

    SciTech Connect (OSTI)

    Bakenov, Zhumabay; Taniguchi, Izumi

    2011-08-15

    Highlights: {yields} We could prepare LiMnPO{sub 4}/C composites by a novel preparation method. {yields} The LiMnPO{sub 4}/C composites were spherical particles with a mean diameter of 3.65 {mu}m. {yields} The LiMnPO{sub 4}/C composite cathode exhibited 112 mAh g{sup -1} at 0.05 C. {yields} It also showed a good rate capability up to 5 C at room temperature and 55 {sup o}C. -- Abstract: Spherical LiMnPO{sub 4}/C composite microparticles were prepared by a combination of spray pyrolysis and spray drying followed by heat treatment and examined as a cathode material for lithium batteries. The structure, morphology and electrochemical performance of the resulting spherical LiMnPO{sub 4}/C microparticles were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electronic microscopy and standard electrochemical techniques. The final sample was identified as a single phase orthorhombic structure of LiMnPO{sub 4} and spherical powders with a geometric mean diameter of 3.65 {mu}m and a geometric standard deviation of 1.34. The electrochemical cells contained the spherical LiMnPO{sub 4}/C microparticles exhibited first discharge capacities of 112 and 130 mAh g{sup -1} at 0.05 C at room temperature and 55 {sup o}C, respectively. These also showed a good rate capability up to 5 C at room temperature and 55 {sup o}C.

  7. Properties of Ga{sub 1-x}Mn{sub x}As with high x (>0.1)

    SciTech Connect (OSTI)

    Chiba, D.; Yu, K. M.; Walukiewicz, W.; Nishitani, Y.; Matsukura, F.; Ohno, H.

    2008-04-01

    We have investigated the magnetic and the crystalline properties of a set of Ga{sub 1-x}Mn{sub x}As layers with high nominal Mn compositions (x=0.101-0.198). Magnetization measurements and combined channeling Rutherford backscattering (c-RBS) and particle induced x-ray emission (c-PIXE) measurements have been performed to determine the effective Mn composition x{sub eff} and the fraction of Mn atoms at various lattice sites. Here, x{sub eff} determined from magnetization measurements, which increases with increasing x, is consistent with the results determined from c-RBS-PIXE measurements.

  8. Peculiarly strong room-temperature ferromagnetism from low Mn-doping in ZnO grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Zuo Zheng; Morshed, Muhammad; Liu Jianlin; Beyermann, W. P.; Zheng Jianguo; Xin Yan

    2013-03-15

    Strong room-temperature ferromagnetism is demonstrated in single crystalline Mn-doped ZnO thin films grown by molecular beam epitaxy. Very low Mn doping concentration is investigated, and the measured magnetic moment is much larger than what is expected for an isolated ion based on Hund's rules. The ferromagnetic behavior evolves with Mn concentration. Both magnetic anisotropy and anomalous Hall effect confirm the intrinsic nature of ferromagnetism. While the Mn dopant plays a crucial role, another entity in the system is needed to explain the observed large magnetic moments.

  9. Mn-Stabilized Zirconia: From Imitation Diamonds to a New Potential High-T{sub C} Ferromagnetic Spintronics Material

    SciTech Connect (OSTI)

    Ostanin, S.; Ernst, A.; Sandratskii, L. M.; Bruno, P.; Daene, M.; Hergert, W.; Mertig, I.; Hughes, I. D.; Staunton, J. B.; Kudrnovsky, J.

    2007-01-05

    From the basis of ab initio electronic structure calculations which include the effects of thermally excited magnetic fluctuations, we predict Mn-stabilized cubic zirconia to be ferromagnetic above 500 K. We find this material, which is well known both as an imitation diamond and as a catalyst, to be half-metallic with the majority and minority spin Mn impurity states lying in zirconia's wide gap. The Mn concentration can exceed 40%. The high-T{sub C} ferromagnetism is robust to oxygen vacancy defects and to how the Mn impurities are distributed on the Zr fcc sublattice. We propose this ceramic as a promising future spintronics material.

  10. Enhanced ferromagnetic order in Sr{sub 4}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} featuring canted [MnO{sub 4}]{sub ∞} spin chains of mixed-valent Mn(III)/Mn(IV). Aliovalent substitution of the Sr{sub 4−x}Ln{sub x}Mn{sup III}{sub 2+x}Mn{sup IV}{sub 1−x}O{sub 3}(GeO{sub 4}){sub 3} solid-solution

    SciTech Connect (OSTI)

    West, J. Palmer; Sulejmanovic, Dino; Becht, Gregory; He, Jian; Hitchcock, Dale; Yan, Yonggao; Hwu, Shiou-Jyh

    2013-10-15

    Crystals of Sr{sub 4−x}Ln{sub x}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} (x=0; x∼0.15 for Ln=La, Pr, Nd, Sm. Eu, Gd, Dy; x∼0.3 for Ln=Gd) were isolated upon using high-temperature, solid-state methods in molten-salt media. These compounds are isostructural with the previously reported Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3} (Ln=La, Sm, Gd) series that contains the same [MnO{sub 4}]{sub ∞} spin chains. The synthesis of the Sr{sub 4}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} (x=0) phase was carried out by a double aliovalent substitution with respect to the Sr{sup 2+} and Ge{sup 4+} ions that replace Na{sup +}/Ln{sup 3+} and As{sup 5+} in Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3}, respectively. The title series contains mixed-valent Mn(III)/Mn(IV) and shows a limited range of solid solution, both of which were not observed in the previously reported Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3} series. To form the Sr{sub 4−x}Ln{sub x}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} solid solution, one of the Sr{sup 2+} sites, i.e., the original Ln-site in Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3}, is partially substituted by Ln{sup 3+} in a statistical disorder of Sr{sub 1−x}/Ln{sub x}. Initial magnetic investigations of selected derivatives reveal higher ferromagnetic ordering temperatures than those reported for the Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3} series, presumably attributed to a lesser degree of canting as a result of introducing non-Jahn–Teller Mn{sup 4+} ions. Also intriguing is the observation of multiple anomalies at low temperatures which appear to be of electronic origins. - Graphical abstract: Sr{sub 4−x}Ln{sub x}Mn(III){sub 2+x}Mn(IV){sub 1−x}O{sub 3}(GeO{sub 4}){sub 3}. Display Omitted - Highlights: • Double aliovalent substitution: Sr{sub 4}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} with respect to Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3}. • Solid solution with respect to statistical disorder of Sr{sub 1

  11. Disorder dependent half-metallicity in Mn{sub 2}CoSi inverse Heusler alloy

    SciTech Connect (OSTI)

    Singh, Mukhtiyar; Saini, Hardev S.; Thakur, Jyoti; Reshak, Ali H.; Kashyap, Manish K.

    2013-12-15

    Heusler alloys based thin-films often exhibit a degree of atomic disorder which leads to the lowering of spin polarization in spintronic devices. We present ab-initio calculations of atomic disorder effects on spin polarization and half-metallicity of Mn{sub 2}CoSi inverse Heusler alloy. The five types of disorder in Mn{sub 2}CoSi have been proposed and investigated in detail. The A2{sub a}-type and B2-type disorders destroy the half-metallicity whereas it sustains for all disorders concentrations in DO{sub 3a}- and A2{sub b}-type disorder and for smallest disorder concentration studied in DO{sub 3b}-type disorder. Lower formation energy/atom for A2{sub b}-type disorder than other four disorders in Mn{sub 2}CoSi advocates the stability of this disorder. The total magnetic moment shows a strong dependence on the disorder and the change in chemical environment. The 100% spin polarization even in the presence of disorders explicitly supports that these disorders shall not hinder the use of Mn{sub 2}CoSi inverse Heusler alloy in device applications. - Graphical abstract: Minority-spin gap (E{sub g↓}) and HM gap (E{sub sf}) as a function of concentrations of various possible disorder in Mn{sub 2}CoSi inverse Heusler alloy. The squares with solid line (black color)/dotted line (blue color)/dashed line (red color) reperesents E{sub g↓} for DO{sub 3a}-/DO{sub 3b}-/A2{sub b}-type disorder in Mn{sub 2}CoSi and the spheres with solid line (black color)/dottedline (blue color)/dashed line (red color) represents E{sub sf} for DO{sub 3a}-/DO{sub 3b}-/A2{sub b}-type disorder in Mn{sub 2}CoSi. - Highlights: • The DO{sub 3}- and A2-type disorders do not affect the half-metallicity in Mn{sub 2}CoSi. • The B2-type disorder solely destroys half-metallicity in Mn{sub 2}CoSi. • The A2-type disorder most probable to occur out of all three types. • The total spin magnetic moment strongly depends on the disorder concentrations.

  12. Comparison of LiMnPO4 made by Combustion and Hydrothermal Syntheses

    SciTech Connect (OSTI)

    Chen, Jiajun; Doeff, Marca M.; Wang, Ruigang

    2008-05-15

    Among the olivine-structured metal phosphate family, LiMnPO{sub 4} exhibits a high discharge potential (4V), which is still compatible with common electrolytes, making it interesting for use in the next generation of Li ion batteries. The extremely low electronic conductivity of this material severely limits its electrochemical performance, however. One strategy to overcome this limitation is to make LiMnPO{sub 4} nanoparticulate to decrease the diffusion distance. Another is to add a carbon or other conductive coating in intimate contact with the nanoparticles of the main phase, as is commonly done with LiFePO{sub 4}. The electrochemical performance of LiFePO{sub 4} is highly dependent on the quality of the carbon coatings on the particles [1-2], among other variables. Combustion synthesis allows the co-synthesis of nanoparticles coated with carbon in one step. Hydrothermal synthesis is used industrially to make LiFePO{sub 4} cathode materials [3] and affords a good deal of control over purity, crystallinity, and particle size. A wide range of olivine-structured materials has been successfully prepared by this technique [4], including LiMnPO{sub 4} in this study. In this paper, we report on the new synthesis of nano-LiMnPO{sub 4} by a combustion method. The purity is dependent upon the conditions used for synthesis, including the type of fuel and precursors that are chosen. The fuel to nitrate ratio influences the combustion temperature, which determines the type and amount of carbon found in the LiMnPO{sub 4} composites. This can further be modified by use of carbon structural modifiers added during a subsequent (optional) calcination step. Figure 1 shows a transmission electron microscopy (TEM) image of the spherical nano-sized LiMnPO{sub 4} particles typically formed by combustion synthesis. The average particle size is around 30 nm, in agreement with values obtained by the Rietveld refinement of XRD patterns. The small size of the particles cause the peak

  13. Comparison of LiMnPO4 made by Combustion and Hydrothermal Syntheses

    SciTech Connect (OSTI)

    Chen, Jiajun; Doeff, Marca M.; Wang, Ruigang

    2008-10-12

    Among the olivine-structured metal phosphate family, LiMnPO{sub 4} exhibits a high discharge potential (4V), which is still compatible with common electrolytes, making it interesting for use in the next generation of Li ion batteries. The extremely low electronic conductivity of this material severely limits its electrochemical performance, however. One strategy to overcome this limitation is to make LiMnPO{sub 4} nanoparticulate to decrease the diffusion distance. Another is to add a carbon or other conductive coating in intimate contact with the nanoparticles of the main phase, as is commonly done with LiFePO{sub 4}. The electrochemical performance of LiFePO{sub 4} is highly dependent on the quality of the carbon coatings on the particles, among other variables. Combustion synthesis allows the co-synthesis of nanoparticles coated with carbon in one step. Hydrothermal synthesis is used industrially to make LiFePO{sub 4} cathode materials and affords a good deal of control over purity, crystallinity, and particle size. A wide range of olivine-structured materials has been successfully prepared by this technique, including LiMnPO{sub 4} in this study. In this paper, we report on the new synthesis of nano-LiMnPO{sub 4} by a combustion method. The purity is dependent upon the conditions used for synthesis, including the type of fuel and precursors that are chosen. The fuel to nitrate ratio influences the combustion temperature, which determines the type and amount of carbon found in the LiMnPO{sub 4} composites. This can further be modified by use of carbon structural modifiers added during a subsequent (optional) calcination step. Figure 1 shows a transmission electron microscopy (TEM) image of the spherical nano-sized LiMnPO{sub 4} particles typically formed by combustion synthesis. The average particle size is around 30 nm, in agreement with values obtained by the Rietveld refinement of XRD patterns. The small size of the particles cause the peak broadening evident

  14. Magnetic susceptibilities of liquid Cr-Au, Mn-Au and Fe-Au alloys

    SciTech Connect (OSTI)

    Ohno, S.; Shimakura, H.; Tahara, S.; Okada, T.

    2015-08-17

    The magnetic susceptibility of liquid Cr-Au, Mn-Au, Fe-Au and Cu-Au alloys was investigated as a function of temperature and composition. Liquid Cr{sub 1-c}Au{sub c} with 0.5 ≤ c and Mn{sub 1-c}Au{sub c} with 0.3≤c obeyed the Curie-Weiss law with regard to their dependence of χ on temperature. The magnetic susceptibilities of liquid Fe-Au alloys also exhibited Curie-Weiss behavior with a reasonable value for the effective number of Bohr magneton. On the Au-rich side, the composition dependence of χ for liquid TM-Au (TM=Cr, Mn, Fe) alloys increased rapidly with increasing TM content, respectively. Additionally, the composition dependences of χ for liquid Cr-Au, Mn-Au, and Fe-Au alloys had maxima at compositions of 50 at% Cr, 70 at% Mn, and 85 at% Fe, respectively. We compared the composition dependences of χ{sub 3d} due to 3d electrons for liquid binary TM-M (M=Au, Al, Si, Sb), and investigated the relationship between χ{sub 3d} and E{sub F} in liquid binary TM-M alloys at a composition of 50 at% TM.

  15. Extended magnetic exchange interactions in the high-temperature ferromagnet MnBi

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Christianson, Andrew D.; Hahn, Steven E.; Fishman, Randy Scott; Parker, David S.; McGuire, Michael A.; Sales, Brian C.; Lumsden, Mark D.; Williams, T. J.; Taylor, A. E.

    2016-05-09

    Here, the high-temperature ferromagnet MnBi continues to receive attention as a candidate to replace rare-earth-containing permanent magnets in applications above room temperature. This is due to a high Curie temperature, large magnetic moments, and a coercivity that increases with temperature. The synthesis of MnBi also allows for crystals that are free of interstitial Mn, enabling more direct access to the key interactions underlying the physical properties of binary Mn-based ferromagnets. In this work, we use inelastic neutron scattering to measure the spin waves of MnBi in order to characterize the magnetic exchange at low temperature. Consistent with the spin reorientationmore » that occurs below 140~K, we do not observe a spin gap in this system above our experimental resolution. A Heisenberg model was fit to the spin wave data in order to characterize the long-range nature of the exchange. It was found that interactions up to sixth nearest neighbor are required to fully parameterize the spin waves. Surprisingly, the nearest-neighbor term is antiferromagnetic, and the realization of a ferromagnetic ground state relies on the more numerous ferromagnetic terms beyond nearest neighbor, suggesting that the ferromagnetic ground state arises as a consequence of the long-ranged interactions in the system.« less

  16. Novel Solar Energy Conversion Materials by Design of Mn(II) Oxides

    SciTech Connect (OSTI)

    Lany, S.; Peng, H.; Ndione, P.; Zakutayev, A.; Ginley, D. S.

    2013-01-01

    Solar energy conversion materials need to fulfill simultaneously a number of requirements in regard of their band-structure, optical properties, carrier transport, and doping. Despite their desirable chemical properties, e.g., for photo-electrocatalysis, transition-metal oxides usually do not have desirable semiconducting properties. Instead, oxides with open cation d-shells are typically Mott or charge-transfer insulators with notoriously poor transport properties, resulting from large effective electron/hole masses or from carrier self-trapping. Based on the notion that the electronic structure features (p-d interaction) supporting the p-type conductivity in d10 oxides like Cu2O and CuAlO2 occurs in a similar fashion also in the d5 (high-spin) oxides, we recently studied theoretically the band-structure and transport properties of the prototypical binary d5 oxides MnO and Fe2O3 [PRB 85, 201202(R)]. We found that MnO tends to self-trap holes by forming Mn+III, whereas Fe2O3 self-traps electrons by forming Fe+II. However, the self-trapping of holes is suppressed by when Mn is tetrahedrally coordinated, which suggests specific routes to design novel solar conversion materials by considering ternary Mn(II) oxides or oxide alloys. We are presenting theory, synthesis, and initial characterization for these novel energy materials.

  17. Electronic structure and the origin of the Dzyaloshinskii-Moriya interaction in MnSi

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Satpathy, S.; Shanavas, K. V.

    2016-05-02

    Here, the metallic helimagnet MnSi has been found to exhibit skyrmionic spin textures when subjected to magnetic fields at low temperatures. The Dzyaloshinskii-Moriya (DM) interaction plays a key role in stabilizing the skyrmion state. With the help of first-principles calculations, crystal field theory and a tight-binding model we study the electronic structure and the origin of the DM interaction in the B20 phase of MnSi. The strength ofmore » $$\\vec{D}$$ parameter is determined by the magnitude of the spin-orbit interaction and the degree of orbital mixing, induced by the symmetry-breaking distortions in the B20 phase. We find that, strong coupling between Mn-$d$ and Si-$p$ states lead to a mixed valence ground state $$|d^{7-x}p^{2+x}\\rangle$$ configuration. The experimental magnetic moment of $$0.4~\\mu_B$$ is consistent with the Coulomb-corrected DFT+$U$ calculations, which redistributes electrons between the majority and minority spin channels. We derive the magnetic interaction parameters $J$ and $$\\vec{D}$$ for Mn-Si-Mn superexchange paths using Moriya's theory assuming the interaction to be mediated by $e_g$ electrons near the Fermi level. Using parameters from our calculations, we get reasonable agreement with the observations.« less

  18. High-Resolution Structure of the Photosynthetic Mn4Ca Catalyst from X-ray Spectroscopy

    SciTech Connect (OSTI)

    Yachandra, Vittal; Yano, Junko; Kern, Jan; Pushkar, Yulia; Sauer, Kenneth; Glatzel, Pieter; Bergmann, Uwe; Messinger, Johannes; Zouni, Athina; Yachandra, Vittal K.

    2007-08-01

    The application of high-resolution X-ray spectroscopy methods to study the photosynthetic water oxidizing complex, which contains a unique hetero-nuclear catalytic Mn4Ca cluster, are described. Issues of X-ray damage especially at the metal sites in the Mn4Ca cluster are discussed. The structure of the Mn4Ca catalyst at high-resolution which has so far eluded attempts of determination by X-ray diffraction, EXAFS and other spectroscopic techniques has been addressed using polarized EXAFS techniques applied to oriented PS II membrane preparations and PS II single crystals. A review of how the resolution of traditional EXAFS techniques can be improved, using methods such as range-extended EXAFS is presented, and the changes that occur in the structure of the cluster as it advances through the catalytic cycle are described. X-ray absorption and emission techniques (XANES and K? emission) have been used earlier to determine the oxidation states of the Mn4Ca cluster, and in this report we review the use of X-ray resonant Raman spectroscopy to understand the electronic structure of the Mn4Ca cluster as it cycles through the intermediate S-states.

  19. Electronic structural and magnetic properties of Mn{sub 5}Ge{sub 3} clusters

    SciTech Connect (OSTI)

    Yuan, H. K.; Chen, H. Kuang, A. L.; Tian, C. L.; Wang, J. Z.

    2013-11-28

    Theoretical understanding of the stability, ferromagnetism, and spin polarization of Mn{sub 5}Ge{sub 3} clusters has been performed by using the density functional theory with generalized gradient approximation for exchange and correlation. The magnetic moments and magnetic anisotropy energy (MAE) have been calculated for both bulk and clusters, and the enhanced magnetic moment as well as the enlarged MAE have been identified in clusters. The most attractive achievement is that Mn{sub 5}Ge{sub 3} clusters show a fine half-metallic character with large energy scales. The present results may have important implications for potential applications of small Mn{sub 5}Ge{sub 3} clusters as both emerging spintronics and next-generation data-storage technologies.

  20. Elasticity and magnetocaloric effect in MnFe4Si3

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Herlitschke, Marcus; Klobes, B.; Sergueev, I.; Hering, Paul; Persson, Joerg; Hermann, Raphael P.

    2016-03-16

    The room temperature magnetocaloric material MnFe4Si3 was investigated with nuclear inelastic scattering (NIS) and resonant ultrasound spectroscopy (RUS) at different temperatures and applied magnetic fields in order to assess the infuence of the magnetic transition and the magnetocaloric effect on the lattice dynamics. The NIS data give access to phonons with energies above 3 meV, whereas RUS probes the elasticity of the material in the MHz frequency range and thus low energy, ~5 neV, phonon modes. A significant infuence of the magnetic transition on the lattice dynamics is observed only in the low energy region. Here, MnFe4Si3 and other compoundsmore » in the Mn5-xFexSi3 series were also investigated with vibrating sample magnetometry, resistivity measurements and Moessbauer spectroscopy in order to study the magnetic transitions and to complement the obtained results on the lattice dynamics.« less

  1. Theoretical study on the role of dynamics on the unusual magnetic properties in MnBi

    SciTech Connect (OSTI)

    Shanavas, K. V.; Parker, David; Singh, David J.

    2014-11-27

    Here we study the electronic structure and lattice dynamics in the ferromagnet MnBi using first-principles calculations and a tight-binding model. The band structure around the Fermi level is dominated by Bi-p states which are the primary contributors to the magnetic anisotropy energy in the low temperature structure. A tight-binding model consisting of Mn-d and Bi-p states is developed and the parameters are determined from first-principles calculations. Phonon dispersions and elastic moduli exhibit several interesting features. In conclusion, the results imply that the magnetic interaction with the crystal lattice in MnBi is considerably more complex than previously thought and in particular that there is a rich interplay between phonons and magnetism involving both magnetoelastic and magnetostrictive coupling.

  2. Theoretical study on the role of dynamics on the unusual magnetic properties in MnBi

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Shanavas, K. V.; Parker, David; Singh, David J.

    2014-11-27

    Here we study the electronic structure and lattice dynamics in the ferromagnet MnBi using first-principles calculations and a tight-binding model. The band structure around the Fermi level is dominated by Bi-p states which are the primary contributors to the magnetic anisotropy energy in the low temperature structure. A tight-binding model consisting of Mn-d and Bi-p states is developed and the parameters are determined from first-principles calculations. Phonon dispersions and elastic moduli exhibit several interesting features. In conclusion, the results imply that the magnetic interaction with the crystal lattice in MnBi is considerably more complex than previously thought and in particularmore » that there is a rich interplay between phonons and magnetism involving both magnetoelastic and magnetostrictive coupling.« less

  3. Anomalous magnetic configuration of Mn{sub 2}NiAl ribbon and the role of hybridization in the martensitic transformation of Mn{sub 50}Ni{sub 50−x}Al{sub x} ribbons

    SciTech Connect (OSTI)

    Zhao, R. B.; Zhao, D. W.; Li, G. K.; Ma, L. E-mail: houdenglu@mail.hebtu.edu.cn; Zhen, C. M.; Hou, D. L. E-mail: houdenglu@mail.hebtu.edu.cn; Wang, W. H.; Liu, E. K.; Chen, J. L.; Wu, G. H.

    2014-12-08

    The magnetic configuration of Mn{sub 2}NiAl ribbon has been investigated. In contrast to Ni{sub 2}MnAl, the compound Mn{sub 2}NiAl with considerable disorder does exhibit ferromagnetism and, due to exchange interaction competition, both ferromagnetic and antiferromagnetic moment orientations can coexist between nearest neighbor Mn atoms. This is unexpected in Heusler alloys. Regarding the mechanism of the martensitic transformation in Mn{sub 50}Ni{sub 50−x}Al{sub x}, it is found that increasing the Al content results in an unusual change in the lattice constant, a decrease of the transformation entropy change, and enhancement of the calculated electron localization. These results indicate that the p-d covalent hybridization between Mn (or Ni) and Al atoms gradually increases at the expense of the d-d hybridization between Ni and Mn atoms. This leads to an increased stability of the austenite phase and a decrease of the martensitic transformation temperature. For 11 ≤ x ≤ 14, Mn{sub 50}Ni{sub 50−x}Al{sub x} ferromagnetic shape memory alloys are obtained.

  4. Enhanced performance of branched TiO{sub 2} nanorod based Mn-doped CdS and Mn-doped CdSe quantum dot-sensitized solar cell

    SciTech Connect (OSTI)

    Kim, Soo-Kyoung; Gopi, Chandu V. V. M.; Lee, Jae-Cheol; Kim, Hee-Je

    2015-04-28

    TiO{sub 2} branched nanostructures could be efficient as photoanodes for quantum dot-sensitized solar cells (QDSCs) due to their large surface area for QD deposition. In this study, Mn-doped CdS/Mn-doped CdSe deposited branched TiO{sub 2} nanorods were fabricated to enhance the photovoltaic performance of QDSCs. Mn doping in CdS and CdSe retards the recombination losses of electrons, while branched TiO{sub 2} nanorods facilitate effective electron transport and compensate for the low surface area of the nanorod structure. As a result, the charge-transfer resistance (R{sub CT}), electron lifetime (?{sub e}), and the amount of QD deposition were significantly improved with branched TiO{sub 2} nanorod based Mn-doped CdS/Mn-doped CdSe quantum dot-sensitized solar cell.

  5. Perpendicularly magnetized {tau}-MnAl (001) thin films epitaxied on GaAs

    SciTech Connect (OSTI)

    Nie, S. H.; Zhu, L. J.; Lu, J.; Pan, D.; Wang, H. L.; Yu, X. Z.; Xiao, J. X.; Zhao, J. H.

    2013-04-15

    Perpendicularly magnetized {tau}-MnAl films have been epitaxied on GaAs (001) by molecular-beam epitaxy. Crystalline quality and magnetic properties of the samples were strongly dependent on growth temperature. The highest coercivity of 10.7 kOe, saturation magnetization of 361.4 emu/cm{sup 3}, perpendicular magnetic anisotropy constant of 13.65 Merg/cm{sup 3}, and magnetic energy product of 4.44 MGOe were achieved. These tunable magnetic properties make MnAl films valuable as excellent and cost-effective alternative for not only high density perpendicular magnetic recording storage and spintronics devices but also permanent magnets.

  6. MnO spin-wave dispersion curves from neutron powder diffraction

    SciTech Connect (OSTI)

    Goodwin, Andrew L.; Dove, Martin T.; Tucker, Matthew G.; Keen, David A.

    2007-02-15

    We describe a model-independent approach for the extraction of spin-wave dispersion curves from powder neutron total scattering data. Our approach is based on a statistical analysis of real-space spin configurations to calculate spin-dynamical quantities. The RMCPROFILE implementation of the reverse Monte Carlo refinement process is used to generate a large ensemble of supercell spin configurations from MnO powder diffraction data collected at 100 K. Our analysis of these configurations gives spin-wave dispersion curves for MnO that agree well with those determined independently using neutron triple-axis spectroscopic techniques.

  7. Antiferromagentic resonance detected by direct current voltages in MnF{sub 2}/Pt bilayers

    SciTech Connect (OSTI)

    Ross, Philipp; Schreier, Michael Lotze, Johannes; Huebl, Hans; Goennenwein, Sebastian T. B.; Gross, Rudolf

    2015-12-21

    We performed coplanar waveguide-based broadband ferromagnetic resonance experiments on the antiferromagnetic insulator MnF{sub 2}, while simultaneously recording the DC voltage arising in a thin platinum film deposited onto the MnF{sub 2}. The antiferromagnetic resonance is clearly reflected in both the transmission through the waveguide as well as the DC voltage in the Pt strip. The DC voltage remains largely unaffected by field reversal and thus presumably stems from microwave rectification and/or heating effects. However, we identify a small magnetic field orientation dependent contribution, compatible with antiferromagnetic spin pumping theory.

  8. Fabrication of (Mn,Co)3O4 Surface Coatings onto Alloy Substrates

    SciTech Connect (OSTI)

    Yang, Zhenguo; Xia, Guanguang; Li, Xiaohong S.; Singh, Prabhakar; Stevenson, Jeffry W.

    2007-04-30

    Ferritic stainless steels are promising candidates for IT-SOFC interconnect applications due to their low cost and resistance to oxidation at SOFC operating temperatures. However, several challenges remain, including long term electrical conductivity and surface stability under interconnect exposure conditions and chromia scale evaporation. One means of extending interconnect lifetime and improving performance is to apply a protective coating, such as (Mn,Co)3O4 spinel, to the cathode side of the interconnect. These coatings have proven effective in reducing scale growth kinetics and Cr volatility. This report describes several procedures developed at PNNL for fabricating (Mn,Co)3O4 spinel coatings onto ferritic stainless steels.

  9. Unoccupied electronic structure of Ni2MnGa ferromagnetic shape memory alloy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Maniraj, M.; D׳Souza, S. W.; Rai, Abhishek; Schlagel, D. L.; Lograsso, T. A.; Iowa State Univ., Ames, IA; Chakrabarti, Aparna; Barman, S. R.

    2015-08-20

    Momentum resolved inverse photoemission spectroscopy measurements show that the dispersion of the unoccupied bands of Ni2MnGa is significant in the austenite phase. Furthermore, in the martensite phase, it is markedly reduced, which is possibly related to the structural transition to an incommensurate modulated state in the martensite phase. Finally, based on the first principle calculations of the electronic structure of Ni–Mn–Ga, we show that the modification of the spectral shape with surface composition is related to change in the hybridization between the Mn 3d and Ni 3d-like states that dominate the unoccupied conduction band.

  10. Study of lattice dynamics in yttrium doped NdMnO{sub 3} using Raman spectroscopy

    SciTech Connect (OSTI)

    Yadav, Ruchika Elizabeth, Suja; Nair, Harikrishnan S.

    2014-04-24

    A systematic study of Raman spectra on Yttrium doped NdMnO{sub 3} polycrystalline samples was undertaken to understand the lattice dynamics in this compound. Raman active phonons were analyzed and the observed peak were assigned to elucidate various phonon modes in the range (200 - 800) cm{sup −1}. It was observed that at 325 cm{sup −1} phonon frequency shifts upward as much as upto 4 % with increase in Yttrium content. Lattice distortions manifest themselves by frequency shifts in both bending and tilt modes of MnO{sub 6} octahedra, resulting in increase of Raman band line-widths.

  11. Orbital two-channel Kondo effect in epitaxial ferromagnetic L10-MnAl films

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Journal Article: Orbital two-channel Kondo effect in epitaxial ferromagnetic L10-MnAl films Citation Details In-Document Search Title: Orbital two-channel Kondo effect in epitaxial ferromagnetic L10-MnAl films The orbital two-channel Kondo effect displaying exotic non-Fermi liquid behaviour arises in the intricate scenario of two conduction electrons compensating a pseudo-spin-1/2 impurity of two-level system. Despite extensive efforts for several decades,

  12. Structural transformations in Mn{sub 2}NiGa due to residual stress

    SciTech Connect (OSTI)

    Singh, Sanjay; Maniraj, M.; D'Souza, S. W.; Barman, S. R.; Ranjan, R.

    2010-02-22

    Powder x-ray diffraction study of Mn{sub 2}NiGa ferromagnetic shape memory alloy shows the existence of a 7M monoclinic modulated structure at room temperature (RT). The structure of Mn{sub 2}NiGa is found to be highly dependent on residual stress. For higher stress, the structure is tetragonal at RT, and for intermediate stress it is 7M monoclinic. However, only when the stress is considerably relaxed, the structure is cubic, as is expected at RT since the martensitic transition temperature is 230 K.

  13. Modeling and Characterization of the Magnetocaloric Effect in Ni2MnGa Materials

    SciTech Connect (OSTI)

    Nicholson, Don M; Odbadrakh, Khorgolkhuu; Shassere, Benjamin; Rios, Orlando; Hodges, Jason P; Ludtka, Gerard Michael; Porter, Wallace D; Safa-Sefat, Athena; Rusanu, Aurelian; Brown, Greg; Evans III, Boyd Mccutchen

    2014-01-01

    Magnetic shape memory alloys have great promise as magneto-caloric effect refrigerant materials due to their combined magnetic and structural transitions. Computational and experimental research is reported on the Ni2MnGa material system. The magnetic states of this system are explored using the Wang-Landau statistical approach in conjunction with the Locally Self-consistent Multiple-Scattering method. The effects of alloying agents on the transition temperatures of the Ni2MnGa alloy are investigated using differential scanning calorimetry and superconducting quantum interference device. Experiments are performed at the Spallation Neutron Source at Oak Ridge National Laboratory to observe the structural and magnetic phase transformations.

  14. Electron-hole asymmetry, Dirac fermions, and quantum magnetoresistance in BaMnBi2

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, Lijun; Wang, Kefeng; Graf, D.; Wang, Limin; Wang, Aifeng; Petrovic, C.

    2016-03-28

    Here, we report two-dimensional quantum transport and Dirac fermions in BaMnBi2 single crystals. BaMnBi2 is a layered bad metal with highly anisotropic conductivity and magnetic order below 290 K. Magnetotransport properties, nonzero Berry phase, small cyclotron mass, and the first-principles band structure calculations indicate the presence of Dirac fermions in Bi square nets. Quantum oscillations in the Hall channel suggest the presence of both electron and hole pockets, whereas Dirac and parabolic states coexist at the Fermi level.

  15. Study of structural and electronic properties of Mn{sub 3}O{sub 4}

    SciTech Connect (OSTI)

    Kaur, Ramandeep Maitra, Tulika Nautiyal, Tashi

    2014-04-24

    Using density functional theory calculations we have examined the structural and electronic properties of magnetic spinel Mn{sub 3}O{sub 4}. We have optimized the structure (both volume and c/a ratio) within GGA. Then Coulomb correlations are included in the calculations to study the electronic properties. We observe that both the band gap and magnetic moment increase with the increase in Coulomb correlation due to the increased Jahn-Teller splitting and localization of the single e{sub g} electron of Mn{sup 3+}.

  16. Graphene in proximity to magnetic insulating LaMnO{sub 3}

    SciTech Connect (OSTI)

    Cheng, Guanghui; Wei, Laiming, E-mail: laiming@ustc.edu.cn, E-mail: cgzeng@ustc.edu.cn; Cheng, Long; Liang, Haixing; Zhang, Xiaoqiang; Li, Hui [Hefei National Laboratory for Physical Sciences at the Microscale (HFNL) and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Yu, Guolin [Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai 200083 (China); Zeng, Changgan, E-mail: laiming@ustc.edu.cn, E-mail: cgzeng@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at the Microscale (HFNL) and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); International Center for Quantum Design of Functional Materials (ICQD), HFNL, University of Science and Technology of China, Hefei, Anhui 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2014-09-29

    Proximity to functional substrates may enhance the coupling between the quantum degrees of freedom and thus develop nontrivial quantum effects in graphene. Here, we demonstrate the successful fabrication of graphene in proximity to atomically flat magnetic insulating LaMnO{sub 3} films. The insulating nature of the LaMnO{sub 3} films not only ensures the electronic transport only occur in the graphene layers but also allow them to serve as dielectric layers for gating. Transport measurements reveal anomalous behaviors, including asymmetrical longitudinal magnetoresistivity and nonlinear Hall effect. This work may pave a way toward the realization of intriguing quantum phases in graphene.

  17. Enlarged Mn 3s splitting and room-temperature ferromagnetism in epitaxially grown oxygen doped Mn{sub 2}N{sub 0.86} films

    SciTech Connect (OSTI)

    Meng, M.; Wu, S. X. Ren, L. Z.; Zhou, W. Q.; Wang, Y. J.; Wang, G. L.; Li, S. W.

    2014-11-07

    Single-phase and oxygen doped Mn{sub 2}N{sub 0.86} thin films have been grown on MgO (111) by plasma-assisted molecular beam epitaxy. The films grow under tensile strain and, remarkably, they show ferromagnetic-like interactions at low temperature and ferromagnetic ordering agreed well with the Bloch-law T{sup 3/2} at room-temperature. We further demonstrate the enlarged Mn 3s splitting (6.46 eV) and its possible relation to the observed ferromagnetism. Our study not only provide a strategy for further theoretical work on oxygen doped manganese nitrides, but also shed promising light on utilizing its room-temperature FM property to fabricate spintronic devices.

  18. Synthesis of MnO{sub 2}-graphene composites with enhanced supercapacitive performance via pulse electrodeposition under supergravity field

    SciTech Connect (OSTI)

    Liu, Tingting; Shao, Guangjie; Ji, Mingtong; Wang, Guiling

    2014-07-01

    A method of pulse electrodeposition under supergravity field was proposed to synthesize MnO{sub 2}-graphene composites. Supergravity is very efficient for promoting mass transfer and decreasing concentration polarization during the electrodeposition process. The synthesis was conducted on our homemade supergravity equipment. The strength of supergravity field depended on the rotating speed of the ring electrode. 3D flower like MnO{sub 2} spheres composed of nanoflakes were acquired when the rotating speed was 3000 rpm. Graphene nanosheets play as a role of conductive substrates for MnO{sub 2} growing. The composites are evaluated as electrode materials for supercapacitors. Electrochemical results show that the maximum specific capacitance of the MnO{sub 2}-graphene composite is 595.7 F g{sup ?1} at a current density of 0.5 A g{sup ?1}. In addition, the composite exhibits excellent cycle stability with no capacitance attenuation after 1000 cycles. The approach provides new ideas for developing supercapacitor electrode materials with high performance. - Graphical abstract: 3D flower like MnO{sub 2} spheres composed of nanoflakes were acquired at 3000 rpm. - Highlights: MnO{sub 2}-graphene composites were prepared by pulse electrodeposition under supergravity. 3D flower like MnO{sub 2} spheres are anchored on the graphene nanosheets. The MnO{sub 2}-graphene electrode exhibits a specific capacitance of 595.7 F g{sup ?1}.

  19. Microstructures and Mechanical Properties of Compositionally Complex Co-free FeNiMnCr18 FCC Solid Solution Alloy

    SciTech Connect (OSTI)

    Wu, Zhenggang; Bei, Hongbin

    2015-01-01

    Recently,a structurally-simplebutcompositionally-complex FeNiCoMnCr highentropyalloywasfoundto haveexcellentmechanicalproperties(e.g.,highstrengthandductility).Tounderstandthepotentialof using highentropyalloysasstructuralmaterialsforadvancednuclearreactorandpowerplants,itis necessary tohaveathoroughunderstandingoftheirstructuralstabilityandmechanicalpropertiesde- gradation underneutronirradiation.ThisrequiresustodevelopasimilarmodelalloywithoutCobe- cause materialwithCowillmakepost-neutron-irradiationtestingdifficult duetotheproductionofthe 60Co radioisotope.Toachievethisgoal,aFCC-structuredsingle-phasealloywithacompositionof FeNiMnCr18 wassuccessfullydeveloped.Thisnear-equiatomicFeNiMnCr18 alloy hasgoodmalleability and itsmicrostructurecanbecontrolledbythermomechanicalprocessing.Byrollingandannealing,the as-cast elongated-grained-microstructureisreplacedbyhomogeneousequiaxedgrains.Themechanical properties (e.g.,strengthandductility)oftheFeNiMnCr18 alloy arecomparabletothoseoftheequiatomic FeNiCoMnCr highentropyalloy.Bothstrengthandductilityincreasewithdecreasingdeformation temperature,withthelargestdifferenceoccurringbetween293and77K.Extensivetwin-bandswhich are bundlesofnumerousindividualtwinsareobservedwhenitistensile-fracturedat77K.Notwin bands aredetectedbyEBSDformaterialsdeformedat293Kandhigher.Theunusualtemperature-de- pendencies ofUTSanduniformelongationcouldbecausedbythedevelopmentofthedensetwin substructure, twin-dislocationinteractionsandtheinteractionsbetweenprimaryandsecondarytwin- ning systemswhichresultinamicrostructurerefinement andhencecauseenhancedstrainhardening and postponednecking.

  20. Growth of single-crystal {alpha}-MnO{sub 2} nanorods on multi-walled carbon nanotubes

    SciTech Connect (OSTI)

    Chen Yong; Liu Chenguang; Liu Chang; Lu Gaoqing; Cheng Huiming

    2007-11-06

    Single-crystal {alpha}-MnO{sub 2} nanorods were grown on multi-walled carbon nanotubes (MWNTs) in H{sub 2}SO{sub 4} aqueous solution. The morphology and microstructure of the composites were examined by transmission electron microscopy, high-resolution transmission electron microscopy (HRTEM), X-ray diffractometry and energy dispersive spectroscopy (EDS). The results show that {alpha}-MnO{sub 2} single-crystal nanorods with a mean diameter of 15 nm were densely grown on the surface of MWNTs. Those MWNTs/MnO{sub 2} composites were used as an electrode material for supercapacitors, and it was found that the supercapacitor performance using MWNTs/MnO{sub 2} composites was improved largely compared to that using pure MWNTs and {alpha}-MnO{sub 2} nanorod mechanically mixed with MWNTs.

  1. Low frequency sonochemical synthesis of nanoporous amorphous manganese dioxide (MnO{sub 2}) and adsorption of remazol reactive dye

    SciTech Connect (OSTI)

    Hasan, Siti Zubaidah; Yusop, Muhammad Rahimi; Othman, Mohamed Rozali

    2015-09-25

    Nanoporous amorphous-MnO{sub 2} was synthesized by sonochemical process (sonication) on the solid manganese (II) acetate tetrahydrate (Mn(CH{sub 3}COO){sub 2}.4H{sub 2}O) in 0.1 M KMnO{sub 4}. The product was characterized by X-ray diffraction (XRD), morphology of the material was scanned by Field Emission Scanning Electron Microscopy (FE-SEM) and absorptions of MnO{sub 2} bonding was characterized by Fourier Transform Infra-Red Spectrometer (FT-IR). Remazol reactive dye or Red 3BS, was used in the adsorption study using nanoporous amorphous-MnO{sub 2}. In batch experiment, 10 ppm of Remazol reactive dye was used and experiment was carried out at room temperature. Adsorption of Remazol dye on 0.2g synthesized nanoporous amorphous-MnO{sub 2} showed 99 – 100% decolorization.

  2. X-ray absorption spectroscopy of Mn doped ZnO thin films prepared by rf sputtering technique

    SciTech Connect (OSTI)

    Yadav, Ashok Kumar; Jha, S. N.; Bhattacharyya, D.; Haque, Sk Maidul; Shukla, Dinesh; Choudhary, Ram Janay

    2015-11-15

    A set of r.f. sputter deposited ZnO thin films prepared with different Mn doping concentrations have been characterised by Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Spectroscopy (XANES) measurements at Zn, Mn and O K edges and at Mn L{sub 2,3} edges apart from long range structural characterisation by Grazing Incident X-ray Diffraction (GIXRD) technique. Magnetic measurements show room temperature ferromagnetism in samples with lower Mn doping which is however, gets destroyed at higher Mn doping concentration. The results of the magnetic measurements have been explained using the local structure information obtained from EXAFS and XANES measurements.

  3. Observation of Precipitation Evolution in Fe-Ni-Mn-Ti-Al Maraging Steel using Atom Probe Tomography

    SciTech Connect (OSTI)

    Pereloma, E. V.; Stohr, R A; Miller, Michael K; Ringer, S. P.

    2009-01-01

    We describe the full decomposition sequence in an Fe-Ni-Mn-Ti-Al maraging steel during isothermal annealing at 550 C. Following significant pre-precipitation clustering reactions within the supersaturated martensitic solid solution, (Ni,Fe){sub 3}Ti and (Ni,Fe){sub 3}(Al,Mn) precipitates eventually form after isothermal aging for {approx}60 seconds. The morphology of the (Ni,Fe){sub 3}Ti particles changes gradually during aging from predominantly plate-like to rod-like, and, importantly, Mn and Al were observed to segregate to these precipitate/matrix interfaces. The (Ni,Fe){sub 3}(Al,Mn) precipitates occurred at two main locations: uniformly within the matrix and at the periphery of the (Ni,Fe){sub 3}Ti particles. We relate this latter mode of precipitation to the Mn-Al segregation.

  4. MxMn8O16 (M = Ag or K) as promising cathode materials for secondary Mg based batteries: The role of the cation M

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Huang, Jianping; Takeuchi, Esther S.; Altug S. Poyraz; Takeuchi, Kenneth J.; Marschilok, Amy C.

    2016-02-15

    Here, AgxMn8O16 (Ag-OMS-2) and KxMn8O16 (K-OMS-2) were investigated as high voltage cathode materials for Mg based batteries. Both MxMn8O16 materials delivered high initial capacities (>180 mA h g–1), and KxMn8O16 showed high cycle stability with a reversible capacity of >170 mA h g–1 after 20 cycles.

  5. Bulk and surface half-metallicity: The case of D0{sub 3}-type Mn{sub 3}Ge

    SciTech Connect (OSTI)

    Liu, Hao; Gao, G. Y. Hu, Lei; Ni, Yun; Zu, Fengxia; Zhu, Sicong; Wang, Shuling; Yao, K. L.

    2014-01-21

    Motivated by the experimental realization of D0{sub 22}-type Mn{sub 3}Ge (001) films [Kurt et al. Appl. Phys. Lett. 101, 132410 (2012)] and the structural stability of D0{sub 3}-type Heusler alloy Mn{sub 3}Ge [Zhang et al. J. Phys.: Condens. Matter 25, 206006 (2013)], we use the first-principles calculations based on the full potential linearized augmented plane-wave method to investigate the electronic and magnetic properties of D0{sub 3}-type Heusler alloy Mn{sub 3}Ge and its (001) surface. We show that bulk D0{sub 3}-Mn{sub 3}Ge is a half-metallic ferromagnet with the minority-spin energy gap of 0.52 eV and the magnetic moment of 1.00 μ{sub B} per formula unit. The bulk half-metallicity is preserved at the pure Mn-terminated (001) surface due to the large exchange split, but the MnGe-terminated (001) surface destroys the bulk half-metallicity. We also reveal that the surface stabilities are comparable between the D0{sub 3}-Mn{sub 3}Ge (001) and the experimental D0{sub 22}-Mn{sub 3}Ge (001), which indicates the feasibility to grow the Mn{sub 3}Ge (001) films with D0{sub 3} phase other than D0{sub 22} one. The surface half-metallicity and stability make D0{sub 3}-Mn{sub 3}Ge a promising candidate for spintronic applications.

  6. Magnetochromic effect in multiferroic R In <mn>1mn> x Mn x O <mn>3mn> ( R = Tb , Dy)

    SciTech Connect (OSTI)

    Chen, P.; Holinsworth, B. S.; O'Neal, K. R.; Brinzari, T. V.; Mazumdar, D.; Topping, C. V.; Luo, X.; Cheong, S.-W.; Singleton, J.; McGill, S.; Musfeldt, J. L.

    2015-05-26

    We combined high field magnetization and magneto-optical spectroscopy to investigate spin-charge coupling in Mn-substituted rare-earth indium oxides of chemical formula RIn₁₋xMnxO₃ (R=Tb, Dy). The edge states, on-site Mn³⁺d to d excitations, and rare-earth f-manifold excitations all track the magnetization energy due to dominant Zeeman interactions. The field-induced modifications to the rare-earth excitations are quite large because spin-orbit coupling naturally mixes spin and charge, suggesting that the next logical step in the design strategy should be to bring spin-orbit coupling onto the trigonal bipyramidal chromophore site with a 4 or 5d center.

  7. Short- and long-range magnetic order in LaMnAsO

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    McGuire, Michael A.; Garlea, Vasile Ovidiu

    2016-02-02

    The magnetic properties of the layered oxypnictide LaMnAsO have been revisited using neutron scattering and magnetization measurements. The present measurements identify the Néel temperature TN = 360(1) K. Below TN the critical exponent describing the magnetic order parameter is β=0.33–0.35 , consistent with a three-dimensional Heisenberg model. Above this temperature, diffuse magnetic scattering indicative of short-range magnetic order is observed, and this scattering persists up to TSRO = 650(10) K. Morevoer, the magnetic susceptibility shows a weak anomaly at TSRO and no anomaly at TN. Analysis of the diffuse scattering data using a reverse Monte Carlo algorithm indicates that abovemore » TN nearly two-dimensional, short-range magnetic order is present with a correlation length of 9.3(3) Å within the Mn layers at 400 K. The inelastic scattering data reveal a spin gap of 3.5 meV in the long-range ordered state, and strong, low-energy (quasielastic) magnetic excitations emerging in the short-range ordered state. When we compared it with other related compounds correlates the distortion of the Mn coordination tetrahedra to the sign of the magnetic exchange along the layer-stacking direction, and suggests that short-range order above TN is a common feature in the magnetic behavior of layered Mn-based pnictides and oxypnictides.« less

  8. On the structural defects in synthetic {gamma}-MnO{sub 2}s

    SciTech Connect (OSTI)

    Hill, L.I.; Verbaere, A. . E-mail: alain.verbaere@cnrs-imn.fr

    2004-12-01

    In the literature, the {gamma}-MnO{sub 2} structure is considered to be that of ramsdellite (R), in which two types of defects exist. The occurrence of a slab of pyrolusite (r) is named a De Wolff defect and random faults r in R give intergrowths of ramsdellite and pyrolusite, which account well for the global features of many experimental diffraction patterns. The other type of defect results from 'microtwinning', which allows the so-called {epsilon}-MnO{sub 2} to be put with {gamma}-MnO{sub 2} in the same classification. This paper discusses the previous models of defect and what could be the features of the 'microtwinning', giving for each possible model the corresponding expected features in reciprocal space. The results of a selected area electron diffraction study of rather well crystallized samples of {gamma}-MnO{sub 2} are presented. The splitting of particular diffraction spots and new diffuse intensity are interpreted as the first experimental evidence for 'microtwinning', and a model with orientation variants within microdomains embedded in a 'normal' structure is proposed, which is rather different from the previous hypotheses involving parallel twin planes and parallel twin boundaries.

  9. Redox Dynamics of Mixed Metal (Mn, Cr, and Fe) Ultrafine Particles

    SciTech Connect (OSTI)

    Nico, Peter S.; Kumfer, Benjamin M.; Kennedy, Ian M.; Anastasio, Cort

    2008-08-01

    The impact of particle composition on metal oxidation state, and on changes in oxidation state with simulated atmospheric aging, are investigated experimentally in flame-generated nanoparticles containing Mn, Cr, and Fe. The results demonstrate that the initial fraction of Cr(VI) within the particles decreases with increasing total metal concentration in the flame. In contrast, the initial Mn oxidation state was only partly controlled by metal loading, suggesting the importance of other factors. Two reaction pathways, one reductive and one oxidative, were found to be operating simultaneously during simulated atmospheric aging. The oxidative pathway depended upon the presence of simulated sunlight and O{sub 3}, whereas the reductive pathway occurred in the presence of simulated sunlight alone. The reductive pathway appears to be rapid but transient, allowing the oxidative pathway to dominate with longer aging times, i.e. greater than {approx}8 hours. The presence of Mn within the particles enhanced the importance of the oxidative pathway, leading to more net Cr oxidation during aging implying that Mn can mediate oxidation by removal of electrons from other particulate metals.

  10. CaMn2Sb2: Spin waves on a frustrated antiferromagnetic honeycomb lattice

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    McNally, D. E.; Simonson, J. W.; Kistner-Morris, J. J.; Smith, G. J.; Hassinger, J. E.; DeBeer-Schmidt, L.; Kolesnikov, A. I.; Zaliznyak, I.; Aronson, M. C.

    2015-05-22

    We present inelastic neutron scattering measurements of the antiferromagnetic insulator CaMn2Sb2:, which consists of corrugated honeycomb layers of Mn. The dispersion of magnetic excitations has been measured along the H and L directions in reciprocal space, with a maximum excitation energy of ≈ 24 meV. These excitations are well described by spin waves in a Heisenberg model, including first and second neighbor exchange interactions, J1 and J2, in the Mn plane and also an exchange interaction between planes. The determined ratio J2/J1 ≈ 1/6 suggests that CaMn2Sb2: is the first example of a compound that lies very close to themore » mean field tricritical point, known for the classical Heisenberg model on the honeycomb lattice, where the N´eel phase and two different spiral phases coexist. The magnitude of the determined exchange interactions reveal a mean field ordering temperature ≈ 4 times larger than the reported N´eel temperature TN = 85 K, suggesting significant frustration arising from proximity to the tricritical point.« less