Abstract
Structural, electronic, and magnetic properties of a Heusler-type CoFeCrAl alloy have been investigated experimentally and by model calculations, with a focus on the alloy's spin-gapless semiconductivity. The as-quenched samples are ferrimagnetic at room temperature with a Curie temperature of about 456 K, which increases to 540 K after vacuum annealing at 600°C for 2 h. The saturation magnetizations of the as-quenched and 600°C-annealed samples are 1.9 μB/f.u. and 2.1 μB/f.u., respectively, which are very close to the value predicted by the Slater-Pauling curve. The resistivity shows a nearly linear decrease with increasing temperature, from about 930 μΩ cm at 5 K to about 820 μΩ cm at 250 K, with dρ/dT of about -5 × 10-7 Ω cm K-1. We explain this high resistivity and its temperature dependence as imperfect spin-gapless semiconducting behavior, with a negative band-gap parameter of 0.2 eV.
Original language | English (US) |
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Article number | 245002 |
Journal | Journal of Physics D: Applied Physics |
Volume | 48 |
Issue number | 24 |
DOIs | |
State | Published - Jun 24 2015 |
Keywords
- Heusler alloys
- disorder
- spin gapless semiconductor
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Acoustics and Ultrasonics
- Surfaces, Coatings and Films