Competition of [L2.sub.1] and XA ordering in [Fe.sub.2]CoAl Heusler alloy: a first-principles study

The physical properties of [Fe.sub.2]CoAl (FCA) Heusler alloy are systematically investigated using the first-principles calculations within generalized gradient approximation (GGA) and GGA+U. The influence of atomic ordering with respect to the Wyckoff sites on the phase stability, magnetism and ha...

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Bibliographic Details
Published in:The European physical journal. B, Condensed matter physics Condensed matter physics, 2020-08, Vol.93 (5)
Main Authors: Ahmad, Aquil, Das, Amal K, Srivastava, Sanjeev K
Format: Article
Language:English
Subjects:
Copper alloys
Ferromagnetism
Magnetic alloys
Specialty metals industry
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Summary:The physical properties of [Fe.sub.2]CoAl (FCA) Heusler alloy are systematically investigated using the first-principles calculations within generalized gradient approximation (GGA) and GGA+U. The influence of atomic ordering with respect to the Wyckoff sites on the phase stability, magnetism and half metallicity in both the conventional [L2.sub.1] and XA phases of FCA is focused in this study. Various possible hypothetical structures viz., [L2.sub.1], XA-I, and XA-II are prepared by altering atomic occupancies at their Wyckoff sites. At first, we have determined the stable phase of FCA considering various non-magnetic (or paramagnetic), ferromagnetic (FM) and antiferromagnetic (AFM) configurations. Out of these, the ferromagnetic (FM) XA-I structure is found to be energetically most stable. The total magnetic moments per cell are not in agreement with the Slater-Pauling (SP) rule in any phase; therefore, the half-metallicity is not observed in any configurations. However, FM ordered XA-I type FCA shows 78% spin polarization at the Fermi Energy ([E.sub.F]). Interestingly, the results of XA-I type FCA are closely matched with the experimental results.
ISSN:1434-6028
1434-6036
DOI:10.1140/epjb/e2020-100626-4