Structural disorder and magnetism in the spin-gapless semiconductor CoFeCrAl

Authors

Renu Choudhary, Indian Institute of Technology
Parashu Kharel, University of Nebraska-LincolnFollow
Shah R. Valloppilly, University of Nebraska-LincolnFollow
Yunlong Jin, University of Nebraska- LincolnFollow
Andrew O’Connell, University of Nebraska-Lincoln
Yung Huh, South Dakota State UniversityFollow
Simeon Gilbert, South Dakota State University
Arti Kashyap, University of Nebraska-LincolnFollow
David J. Sellmyer, University of Nebraska-LincolnFollow
Ralph A. Skomski, University of Nebraska-LincolnFollow

ORCID IDs

Yunlong Jin

Date of this Version

2016

Citation

AIP ADVANCES 6, 056304 (2016)

http://dx.doi.org/10.1063/1.4943306

Comments

Copyright 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.

Abstract

Disordered CoFeCrAl and CoFeCrSi_0.5Al_0.5 alloys have been investigated experimentally and by first-principle calculations. The melt-spun and annealed samples all exhibit Heusler-type superlattice peaks, but the peak intensities indicate a substantial degree of B2-type chemical disorder. Si substitution reduces the degree of this disorder. Our theoretical analysis also considers several types of antisite disorder (Fe-Co, Fe-Cr, Co-Cr) in Y-ordered CoFeCrAl and partial substitution of Si for Al. The substitution transforms the spin-gapless semiconductor CoFeCrAl into a halfmetallic ferrimagnet and increases the half-metallic band gap by 0.12 eV. Compared CoFeCrAl, the moment of CoFeCrSi_0.5Al_0.5 is predicted to increase from 2.01 μB to 2.50 μB per formula unit, in good agreement with experiment.