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Title: Origin of spin gapless semiconductor behavior in CoFeCrGa: Theory and Experiment

Despite a plethora of materials suggested for spintronic applications, a new class of materials has emerged, namely spin gapless semiconductors (SGS), which offers potentially more advantageous properties than existing ones. These magnetic semiconductors exhibit a finite band gap for one spin channel and a closed gap for the other. Supported by electronic-structure calculations, we report evidence of SGS behavior in equiatomic quaternary CoFeCrGa, having a cubic Heusler (prototype LiMgPdSn) structure but exhibiting chemical disorder (DO3 structure). CoFeCrGa is found to transform from SGS to half-metallic phase under pressure, which is attributed to unique electronic-structure features. The saturation magnetization (MS) was obtained at 8K agrees with the Slater-Pauling rule and the Curie temperature (TC) is found to exceed 400K. Carrier concentration (up to 250K) and electrical conductivity are observed to be nearly temperature independent, prerequisites for SGS. The anomalous Hall coefficient is estimated to be 185S/cm at 5K. Considering the SGS properties and high TC, this material appears to be promising for spintronic applications.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1] ;  [1]
  1. Indian Inst. of Technology (IIT), Mumbai (India)
  2. Defence Metallurgical Research Lab., Hyderabad (India)
  3. Universidade Estadual de Campinas-UNICAMP, Sao Paulo (Brazil)
  4. DCMPMS, Mumbai (India)
  5. Ames Lab. and Iowa State Univ., Ames, IA (United States)
Publication Date:
OSTI Identifier:
1227394
Report Number(s):
IS--J 8743
Journal ID: ISSN 1098-0121; PRBMDO
Grant/Contract Number:
AC02-07CH11358
Type:
Accepted Manuscript
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 92; Journal Issue: 4; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society (APS)
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY