Phase stability and the effect of lattice distortions on electronic properties and half-metallic ferromagnetism of Co <sub>2</sub> FeAl Heusler alloy: an <i>ab initio</i> study
Aquil Ahmad, S K Srivastava, A K Das
Abstract
Abstract Density functional theory calculations within the generalized gradient approximation are employed to study the ground state of Co 2 FeAl. Various magnetic configurations are considered to find out its most stable phase. The ferromagnetic ground state of the Co 2 FeAl is energetically observed with an optimized lattice constant of 5.70 Å. After that, the system was subjected under uniform and non-uniform strains, to see their effects on spin polarization ( P ) and half-metallicity. The effect of spin–orbit coupling is considered in the present study. Half-metallicity (and 100% P ) is retained only under uniform strains started from 0 to +4%, and dropped rapidly from 90% to 16% for the negative strains started from −1% to −6%. We find that the present system is much sensitive under tetragonal distortions as half-metallicity (and 100% P ) is preserved only for the cubic case. The main reason for the loss of half-metallicity is due to the shift of the bands with respect to the Fermi level ( E F ). We also discuss the influence of these results on spintronics devices.