Crystal Structures and Spin Injection Signals of Si/Mg/MgO/Co₂FeAl_0.5Si_0.5 Junctions

Abstract

We investigated the crystal structures and the spin injection signals of Si/Mg/MgO/Co₂FeAl_0.5Si_0.5 (CFAS) junctions deposited by molecule beam epitaxy. The (001)-orientation and the structural ordering of CFAS thin films changed by heating deposition of CFAS and the insertion of Mg layer into Si/MgO interface. Spin injection signals observed at 10 K for the junctions by 3 terminals Hanle measurements. The maximum voltage change, ΔV_MAX, was increased by heating deposition of CFAS and the insertion of Mg layer. It is supposed that the enhancement of spin polarization by the improvement of structural ordering of CFAS or coherent tunneling by (001)-oriented MgO barrier caused the increment of ΔV_MAX.