The interface structure and magnetic and electronic properties of a Co2FeAl0.5Si0.5/MgO/Co2FeAl0.5Si0.5 magnetic tunneling junction

Abstract

Magnetic tunnel junctions (MTJs) consisting of ferromagnet-insulator-ferromagnet sandwiches have attracted significant interest, and the structure of the interfaces in MTJs plays a crucial role in their performance. The interface structure, and magnetic and electronic properties of a Co2FeAl0.5Si0.5/MgO/Co2FeAl0.5Si0.5 MTJ are studied by first-principles calculations. It is found that three interface structures, the Co-, Fe-, and Al-terminated interfaces, are thermally stable. Local density of states calculations show that interface states form at the Fermi level for the Co- and Fe-terminated interfaces, and their half-metallic properties are destroyed. For the Al-terminated interface, half-metallic behavior remains at the interface, and there are no interface states at the Fermi level. This should heavily suppress the spin-flipping and tunneling caused by interface states located at the Fermi level of a Co2FeAl0.5Si0.5/MgO interface, allowing the transport properties of Co2FeAl0.5Si0.5/MgO/Co2FeAl0.5Si0.5 MTJs to be improved.