Structural disorder and magnetism in the spin-gapless semiconductor CoFeCrAl

Renu Choudhary; Parashu Kharel; Shah R. Valloppilly; Yunlong Jin; Andrew O'Connell; Yung Huh; Simeon Gilbert; Arti Kashyap; D. J. Sellmyer; Ralph Skomski

doi:10.1063/1.4943306

Structural disorder and magnetism in the spin-gapless semiconductor CoFeCrAl

Renu Choudhary, Parashu Kharel, Shah R. Valloppilly, Yunlong Jin, Andrew O'Connell, Yung Huh, Simeon Gilbert, Arti Kashyap, D. J. Sellmyer, Ralph Skomski

Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

33 Scopus citations

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 half-metallic 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 μ_B to 2.50 μ_B per formula unit, in good agreement with experiment.

Original language	English (US)
Article number	056304
Journal	AIP Advances
Volume	6
Issue number	5
DOIs	https://doi.org/10.1063/1.4943306
State	Published - May 1 2016

ASJC Scopus subject areas

General Physics and Astronomy

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title = "Structural disorder and magnetism in the spin-gapless semiconductor CoFeCrAl",

abstract = "Disordered CoFeCrAl and CoFeCrSi0.5Al0.5 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 half-metallic ferrimagnet and increases the half-metallic band gap by 0.12 eV. Compared CoFeCrAl, the moment of CoFeCrSi0.5Al0.5 is predicted to increase from 2.01 μB to 2.50 μB per formula unit, in good agreement with experiment.",

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AU - Choudhary, Renu

AU - Kharel, Parashu

AU - Valloppilly, Shah R.

AU - Jin, Yunlong

AU - O'Connell, Andrew

AU - Huh, Yung

AU - Gilbert, Simeon

AU - Kashyap, Arti

AU - Sellmyer, D. J.

AU - Skomski, Ralph

PY - 2016/5/1

Y1 - 2016/5/1

N2 - Disordered CoFeCrAl and CoFeCrSi0.5Al0.5 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 half-metallic ferrimagnet and increases the half-metallic band gap by 0.12 eV. Compared CoFeCrAl, the moment of CoFeCrSi0.5Al0.5 is predicted to increase from 2.01 μB to 2.50 μB per formula unit, in good agreement with experiment.

AB - Disordered CoFeCrAl and CoFeCrSi0.5Al0.5 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 half-metallic ferrimagnet and increases the half-metallic band gap by 0.12 eV. Compared CoFeCrAl, the moment of CoFeCrSi0.5Al0.5 is predicted to increase from 2.01 μB to 2.50 μB per formula unit, in good agreement with experiment.

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Structural disorder and magnetism in the spin-gapless semiconductor CoFeCrAl

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