Electronic, elastic and X-ray spectroscopic properties of direct and inverse full Heusler compounds Co2FeAl and Fe2CoAl, promising materials for spintronic applications: a DFT+U approach

Abstract

Half-metallicity, low magnetic damping and high Curie temperatures (T_C) are crucial for application in spintronics and full Heusler alloys are promising in this regard. Herein, we have considered Co₂FeAl (CFA) and Fe₂CoAl (FCA) as representatives of direct and indirect full Heusler compounds which crystallize in L2₁ and C1_b phases, respectively. The theory of L2₁ type Heusler alloys has been well established; however the fundamental understanding of Fe₂CoAl is still under developed. In this paper, we have employed density functional theory (DFT) to study the electronic, elastic and X-ray spectroscopic properties of Co₂FeAl and Fe₂CoAl. The electron exchange correlations were treated within a generalized gradient approximation (GGA) as the PBE-scheme. In order to include the impact of valence electrons an onsite Coulomb potential is added to GGA as GGA+U. Within GGA and GGA+U, CFA shows half-metallic behaviour but FCA is metallic. The calculated values of the magnetic moment and T_C are in close agreement with the experimental data.