Study of FeCrSn1-xGax Heusler alloys: Tuning Fermi level to attain half-metallic ferromagnetism

Abstract

We report new Heusler alloys based half-metallic ferromagnets obtained by doping of Ga for Sn in FeCrSn using Full-Potential Linearized Augmented Plane Wave method based upon density functional theory. The base compound FeCrSn, a ferromagnetic metal, is selected because a similar system FeVSn is already fabricated experimentally. We thoroughly study FeCrSn1-xGax (x= 0, 0.25, 0.50. 0.75 and 1) systems in the search of maximum spin polarization. We use the well-established technique of Fermi level tuning via doping of different sp-element in Heusler alloys. We observe high spin polarization (99% and 98%) for x = 0.25 and 0.50 doping of Ga in FeCrSn. Our results confirm that Fermi level tuning is an indispensable method to achieve the high spin polarization. The fine-tuning of doping in between x = 0.25 and 0.50 can lead to robust half-metallicity. We also find the total spin magnetic moments for all studied concentrations and discuss its deviation from Slater-Pauling behavior. We are sure that these new alloys with high spin polarization surely inspire the experimentalist to fabricate the same and can be used in future spintronic devices such as magnetic tunnel junctions and spin valves.