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arXiv · 1501.05599

High spin polarization and large spin splitting in equiatomic quaternary CoFeCrAl Heusler alloy

Lakhan Bainsla·A. I. Mallick·A. A. Coelho·A. K. Nigam·B. S. D. Ch. S. Varaprasad·Y. K. Takahashi·Aftab Alam·K. G. Suresh·K. Hono
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Abstract

In this paper, we investigate CoFeCrAl alloy by means of various experimental techniques and ab-initio calculations to look for half-metallic nature. The alloy is found to exist in the cubic Heusler structure, with presence of B2 ordering. Saturation magnetization (MS) value of about 2 Bohr magneton/f.u. is observed at 8 K under ambient pressure, which is in good agreement with the Slater-Pauling rule. MS values are found to be independent of pressure, which is a prerequisite for half-metals. The ab-initio electronic structure calculations predict half-metallic nature for the alloy with a spin slitting energy of 0.31 eV. Importantly, this system shows a high current spin polarization value of 0.67 [with error of 0.02], as deduced from the point contact Andreev reflection (PCAR) measurements. Linear dependence of electrical resistivity with temperature indicates the possibility of reasonably high spin polarization at elevated temperatures (~150 K) as well. All these suggest that CoFeCrAl is a promising material for the spintronic devices.

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Lakhan Bainsla, A. I. Mallick, A. A. Coelho, A. K. Nigam, B. S. D. Ch. S. Varaprasad, Y. K. Takahashi, Aftab Alam, K. G. Suresh, K. Hono. 2015-01-22. High spin polarization and large spin splitting in equiatomic quaternary CoFeCrAl Heusler alloy. https://doi.org/10.1016/j.jmmm.2015.05.095

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