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Title: Effect of disorder on the magnetic and electronic structure of a prospective spin-gapless semiconductor MnCrVAl

Recent discovery of a new class of materials, spin-gapless semiconductors (SGS), has attracted considerable attention in the last few years, primarily due to potential applications in the emerging field of spin-based electronics (spintronics). Here, we investigate structural, electronic, and magnetic properties of one potential SGS compound, MnCrVAl, using various experimental and theoretical techniques. Our calculations show that this material exhibits ≈ 0.5 eV band gap for the majority-spin states, while for the minority-spin it is nearly gapless. The calculated magnetic moment for the completely ordered structure is 2.9 μB/f.u., which is different from our experimentally measured value of almost zero. Here, this discrepancy is explained by the structural disorder. In particular, A2 type disorder, where Mn or Cr atoms exchange their positions with Al atoms, results in induced antiferromagnetic exchange coupling, which, at a certain level of disorder, effectively reduces the total magnetic moment to zero. This is consistent with our x-ray diffraction measurements which indicate the presence of A2 disorder in all of our samples. In addition, we also show that B2 disorder does not result in antiferromagnetic exchange coupling and therefore does not significantly reduce the total magnetic moment.
Authors:
 [1] ;  [2] ;  [2] ;  [3] ; ORCiD logo [1] ;  [4] ;  [2] ;  [2] ;  [3] ;  [4] ;  [3]
  1. South Dakota State Univ., Brookings, SD (United States); Univ. of Nebraska, Lincoln, NE (United States)
  2. Univ. of Northern Iowa, Cedar Falls, IA (United States)
  3. Univ. of Nebraska, Lincoln, NE (United States)
  4. South Dakota State Univ., Brookings, SD (United States)
Publication Date:
Grant/Contract Number:
FG02-04ER46152
Type:
Published Article
Journal Name:
AIP Advances
Additional Journal Information:
Journal Volume: 7; Journal Issue: 5; Journal ID: ISSN 2158-3226
Publisher:
American Institute of Physics (AIP)
Research Org:
South Dakota State Univ., Brookings, SD (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Magnetic moments; X-ray diffraction; Crystal structure; Antiferromagnetism; Lattice constants
OSTI Identifier:
1336847
Alternate Identifier(s):
OSTI ID: 1393521; OSTI ID: 1421283