skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Vacancy-mediated fcc/bcc phase separation in Fe 1-xNi x ultrathin films

Abstract

The phase separation occurring in Fe-Ni thin lms near the Invar composition is studied by using high resolution spectromicroscopy techniques and density functional theory calculations. Annealed at temperatures around 300 C, Fe 0.70Ni 0.30 lms on W(110) break into micron-sized bcc and fcc domains with compositions in agreement with the bulk Fe-Ni phase diagram. Ni is found to be the di using species in forming the chemical heterogeneity. The experimentally-determined energy barrier of 1.59 0.09 eV is identi ed as the vacancy formation energy via density functional theory calculations. Thus, the principal role of the surface in the phase separation process is attributed to vacancy creation without interstitials.

Authors:
 [1];  [2];  [3]; ;  [4];  [1]
  1. Elettra-Sincrotrone Trieste (Italy)
  2. Abdus Salam International Centre for Theoretical Physics, Trieste (Italy); IOM-CNR Democtrios, Trieste (Italy)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
  4. Synchrotron Soleil, Gif-sur-Yvette (France)
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1340413
Report Number(s):
BNL-113254-2016-JA
Journal ID: ISSN 2469-9950; TRN: US1701751
Grant/Contract Number:
SC00112704
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 94; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Mentes, T. O., Stojic, N., Vescovo, E., Ablett, J. M., Nino, M. A., and Locatelli, A. Vacancy-mediated fcc/bcc phase separation in Fe1-xNix ultrathin films. United States: N. p., 2016. Web. doi:10.1103/PhysRevB.94.085402.
Mentes, T. O., Stojic, N., Vescovo, E., Ablett, J. M., Nino, M. A., & Locatelli, A. Vacancy-mediated fcc/bcc phase separation in Fe1-xNix ultrathin films. United States. doi:10.1103/PhysRevB.94.085402.
Mentes, T. O., Stojic, N., Vescovo, E., Ablett, J. M., Nino, M. A., and Locatelli, A. 2016. "Vacancy-mediated fcc/bcc phase separation in Fe1-xNix ultrathin films". United States. doi:10.1103/PhysRevB.94.085402. https://www.osti.gov/servlets/purl/1340413.
@article{osti_1340413,
title = {Vacancy-mediated fcc/bcc phase separation in Fe1-xNix ultrathin films},
author = {Mentes, T. O. and Stojic, N. and Vescovo, E. and Ablett, J. M. and Nino, M. A. and Locatelli, A.},
abstractNote = {The phase separation occurring in Fe-Ni thin lms near the Invar composition is studied by using high resolution spectromicroscopy techniques and density functional theory calculations. Annealed at temperatures around 300 C, Fe0.70Ni0.30 lms on W(110) break into micron-sized bcc and fcc domains with compositions in agreement with the bulk Fe-Ni phase diagram. Ni is found to be the di using species in forming the chemical heterogeneity. The experimentally-determined energy barrier of 1.59 0.09 eV is identi ed as the vacancy formation energy via density functional theory calculations. Thus, the principal role of the surface in the phase separation process is attributed to vacancy creation without interstitials.},
doi = {10.1103/PhysRevB.94.085402},
journal = {Physical Review B},
number = ,
volume = 94,
place = {United States},
year = 2016,
month = 8
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Save / Share:
  • The magnetic and transport properties of half metallic Fe{sub 3}O{sub 4}, which are sensitive to the stoichiometry, are the key issue for applications in spintronics. An anomalous enlargement of the saturation magnetic moment is found in a relatively thick sample of epitaxial Fe{sub 3}O{sub 4} film by post-growth oxidation method. The investigation of the thickness dependence of magnetic moment suggests that the enhanced magnetism moment may come from the existence of oxygen vacancies. First-principles calculations reveal that with oxygen vacancies in Fe{sub 3}O{sub 4} crystal the spin of Fe ions in the tetrahedron site near the vacancy is much easiermore » to switch parallel to the Fe ions in the octahedron site by temperature disturbance, supported by the temperature dependence of magnetic moment of Fe{sub 3}O{sub 4} films in experiment.« less
  • Abstract not provided.
  • The anomalously large gate leakage current observed prior to dielectric breakdown in electrically stressed n{sup +} gate p metal{endash}oxide{endash}semiconductor field-effect transistors is investigated. Carrier separation measurements reveal that the leakage currents are electron tunneling current, and in some cases are accompanied by noticeable hole-related current at low gate voltages. Experimental results demonstrate the close correlation between this phenomenon and soft breakdown in terms of current{endash}voltage characteristics. {copyright} 2001 American Institute of Physics.
  • The adsorption of the {pi}-conjugated organic molecule {alpha}-sexithiophene which is widely used in molecular electronics has been studied on Au(111) by low-energy electron diffraction and scanning tunneling microscopy. For monolayer adsorption at room temperature, large, well-ordered domains of flat-lying molecules which arrange in molecular rows are observed. A detailed structure analysis reveals an incommensurate, line-on-line oriented monolayer with one molecule per unit cell. In contrast to the behavior in the three-dimensional bulk structure, flat-lying adsorption introduces molecular chirality: Right- and left-handed molecules separate into domains of different orientations which are mirror symmetric with respect to the [112] substrate direction. Detailsmore » of the adlayer structure and the chiral self-recognition can be rationalized based on the van der Waals contour of the adsorbed molecules.« less