Effect of interfacial strain on spin injection and spin polarization of Co2CrAl/NaNbO3/Co2CrAl magnetic tunneling junction
1 Department of Physics, National University of Singapore - 2 Science Drive 3, Singapore 117542, Singapore
2 Data Storage Institute, Agency for Science, Technology and Research - 5 Engineering Drive 1, Singapore 117608, Singapore
Received: 1 December 2011
Accepted: 2 July 2012
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 Co2CrAl and ferroelectric perovskite NaNbO3. 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.
PACS: 72.25.Hg – Electrical injection of spin polarized carriers / 73.40.Sx – Metal-semiconductor-metal structures
© EPLA, 2012