Magnetism, electron transport and effect of disorder in CoFeCrAl

P. Kharel, W. Zhang, R. Skomski, S. Valloppilly, Y. Huh, R. Fuglsby, S. Gilbert, D. J. Sellmyer

Research output: Contribution to journalArticle

31 Scopus citations

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 languageEnglish (US)
Article number245002
JournalJournal of Physics D: Applied Physics
Volume48
Issue number24
DOIs
StatePublished - 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

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    Kharel, P., Zhang, W., Skomski, R., Valloppilly, S., Huh, Y., Fuglsby, R., Gilbert, S., & Sellmyer, D. J. (2015). Magnetism, electron transport and effect of disorder in CoFeCrAl. Journal of Physics D: Applied Physics, 48(24), [245002]. https://doi.org/10.1088/0022-3727/48/24/245002