Effect of interfacial strain on spin injection and spin polarization of Co 2CrAl/NaNbO 3/Co 2CrAl magnetic tunneling junction

Abstract

First-principles calculations were carried out to investigate interfacial strain effects on spin injection and spin polarization of a magnetic tunnel junction consisting of half-metallic full-Heusler alloy Co 2CrAl and ferroelectric perovskite NaNbO 3. Spin-dependent coherent tunneling was calculated within the framework of non-equilibrium Green's function technique. Both spin polarization and tunnel magnetoresistance (TMR) are affected by the interfacial strain but their responses to compressive and tensile strains are different. Spin polarization across the interface is fully preserved under a compressive strain due to stronger coupling between interfacial atoms, whereas a tensile strain significantly enhances interface states and leads to substantial drops in spin polarization and TMR. © Copyright EPLA, 2012.