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

P. Kharel; J. Herran; P. Lukashev; Y. Jin; J. Waybright; S. Gilbert; B. Staten; P. Gray; S. Valloppilly; Y. Huh; D. J. Sellmyer

doi:10.1063/1.4972797

AIP Advances (May 2017)

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

P. Kharel,
J. Herran,
P. Lukashev,
Y. Jin,
J. Waybright,
S. Gilbert,
B. Staten,
P. Gray,
S. Valloppilly,
Y. Huh,
D. J. Sellmyer

Affiliations

P. Kharel: Department of Physics, South Dakota State University, Brookings, South Dakota 57007, USA
J. Herran: Department of Chemistry and Biochemistry, University of Northern Iowa, Cedar Falls, Iowa 50614, USA
P. Lukashev: Department of Physics, University of Northern Iowa, Cedar Falls, Iowa 50614, USA
Y. Jin: Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588, USA
J. Waybright: Department of Physics, South Dakota State University, Brookings, South Dakota 57007, USA
S. Gilbert: Department of Physics, South Dakota State University, Brookings, South Dakota 57007, USA
B. Staten: Department of Physics, University of Northern Iowa, Cedar Falls, Iowa 50614, USA
P. Gray: Department of Computer Science, University of Northern Iowa, Cedar Falls, Iowa 50614, USA
S. Valloppilly: Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588, USA
Y. Huh: Department of Physics, South Dakota State University, Brookings, South Dakota 57007, USA
D. J. Sellmyer: Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588, USA

DOI: https://doi.org/10.1063/1.4972797
Journal volume & issue: Vol. 7, no. 5
pp. 056402 – 056402-6

Abstract

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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. 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.

Published in AIP Advances

ISSN: 2158-3226 (Online)
Publisher: AIP Publishing LLC
Country of publisher: United States
LCC subjects: Science: Physics
Website: http://aipadvances.aip.org/

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