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Title: Stable Calcium Nitrides at Ambient and High Pressures

Authors:
 [1];  [2];  [3];  [4];  [1];  [5]
  1. Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
  2. College of Physics and Electronic Information, Luoyang Normal University, Luoyang 471022, China; Beijing Computational Science Research Center, Beijing 10084, China
  3. Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road NW, Washington, D.C. 20015, United States
  4. Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
  5. Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada; Canadian Light Source, Saskatoon, Saskatchewan S7N 2V3, Canada
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Energy Frontier Research in Extreme Environments (EFree)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1388071
DOE Contract Number:
SC0001057
Resource Type:
Journal Article
Resource Relation:
Journal Name: Inorganic Chemistry; Journal Volume: 55; Journal Issue: 15; Related Information: EFree partners with Carnegie Institution of Washington (lead); California Institute of Technology; Colorado School of Mines; Cornell University; Lehigh University; Pennsylvania State University
Country of Publication:
United States
Language:
English
Subject:
catalysis (heterogeneous), solar (photovoltaic), phonons, thermoelectric, energy storage (including batteries and capacitors), hydrogen and fuel cells, superconductivity, charge transport, mesostructured materials, materials and chemistry by design, synthesis (novel materials)

Citation Formats

Zhu, Shuangshuang, Peng, Feng, Liu, Hanyu, Majumdar, Arnab, Gao, Tao, and Yao, Yansun. Stable Calcium Nitrides at Ambient and High Pressures. United States: N. p., 2016. Web. doi:10.1021/acs.inorgchem.6b00948.
Zhu, Shuangshuang, Peng, Feng, Liu, Hanyu, Majumdar, Arnab, Gao, Tao, & Yao, Yansun. Stable Calcium Nitrides at Ambient and High Pressures. United States. doi:10.1021/acs.inorgchem.6b00948.
Zhu, Shuangshuang, Peng, Feng, Liu, Hanyu, Majumdar, Arnab, Gao, Tao, and Yao, Yansun. 2016. "Stable Calcium Nitrides at Ambient and High Pressures". United States. doi:10.1021/acs.inorgchem.6b00948.
@article{osti_1388071,
title = {Stable Calcium Nitrides at Ambient and High Pressures},
author = {Zhu, Shuangshuang and Peng, Feng and Liu, Hanyu and Majumdar, Arnab and Gao, Tao and Yao, Yansun},
abstractNote = {},
doi = {10.1021/acs.inorgchem.6b00948},
journal = {Inorganic Chemistry},
number = 15,
volume = 55,
place = {United States},
year = 2016,
month = 7
}
  • This paper reports on polycrystalline specimens of pure nickel deformed in uniaxial compression at temperatures of 1000-1550 K, strain rates of 1 {times} 10{sup {minus}5} {minus}3 {times} 10{sup {minus}3} s{sup {minus}1} and pressures of 0.1-1500 MPa, in order to determine the activation parameters of high temperature creep. Experiments at 0.1 MPa were conducted in an MTS apparatus with the specimen immersed in a molten heat-treating salt to prevent oxidation. The data show a decreasing power-law stress exponent with decreasing normalized steady-state flow stress ({sigma}/G), approaching the natural law value of n = 3 at normalized stresses {lt}10{sup {minus}4}. In contrast,more » the activation energy is constant over our range of temperatures (T/T{sub m} = 0.55-0.90), and is indistinguishable from the activation energy of self-diffusion (284 kJ/mol). High pressure experiments were indistinguishable from the activation energy of self-diffusion (284 kJ/mol). High pressure experiments were conducted in a modified piston-cylinder apparatus using the same molten heat-treating salt for the confining medium. The small activation volume could not be resolved; however, the trend of the high pressure data parallels that of the 0.1 MPa data with a systematic offset, and is consistent with the measured activation volume of self diffusion. Specimens deformed at 0.1 MPa exhibited significant strain-enhanced grain growth; this effect is greatly reduced under hydrostatic pressure, whereas subgrain size was less affected.« less
  • Ce{sub 3}Bi{sub 4}Pt{sub 3} is a cerium compound that exhibits a hybridization gap and concomitant semiconducting behavior in the coherent ground state. Using neutron powder diffraction, we have determined the variation of the lattice constant with temperature at two pressures ({ital P}=10{sup {minus}3} and 17.7 kbar), and determined the bulk modulus and atomic mean-square displacements for Ce{sub 3}Bi{sub 4}Pt{sub 3} and its normal analog, La{sub 3}Bi{sub 4}Pt{sub 3}. The thermal expansion {Delta}{beta} in Ce{sub 3}Bi{sub 4}Pt{sub 3} exhibits a maximum at {ital T}{sub max}=50 K at ambient pressure. Below 50 K, the bulk modulus {Delta}{ital B} is proportional to {italmore » T}{Delta}{beta}. We apply a Grueneisen analysis, under the assumption that the free energy exhibits {ital T}/{ital T}{sub 0}({ital V}) scaling. The Grueneisen parameter deduced from the ratio {Delta}{ital B}/{ital T}{Delta}{beta} is consistent with the value {Omega}=36 deduced from the pressure variation of {ital T}{sub max}. The analysis allows us to predict the temperature dependence of the 4{ital f} specific heat ({Delta}{ital C}{proportional to}{Delta}{beta}/{Omega}), which thus has a maximum at 50 K and a high-temperature entropy nearly equal the expected value {ital R} ln6. We argue that the maximum at 50 K reflects an (indirect) hybridization gap of order 100 K. We show further that the lattice constant anomaly {Delta}{ital a}{sub 0} is proportional to the effective moment {ital T}{chi}; this suggests that a relationship known to be valid for antiferromagnets, namely {partial derivative}({ital T}{chi})/{partial derivative}{ital T}{proportional to}{Delta}{ital C} where {Delta}{ital C} is the specific heat, may be valid for Ce{sub 3}Bi{sub 4}Pt{sub 3}.« less
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