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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Mar 04, 2016
- Source ID
- 10.1063/1.4943306
Entities
People
- Andrew O’connell
- Arti Kashyap
- D. J. Sellmyer
- Parashu Kharel
- Ralph Skomski
- Renu Choudhary
- Shah R. Valloppilly
- Simeon Gilbert
- Yung Huh
- Yunlong Jin
Organizations
- Army Research Office
- Indian Institutes of Technology
- Nano Mission Council, Department of Science and Technology
- National Science Foundation
- South Dakota State University
- United States Department of Energy
- University of Nebraska–Lincoln