Tunnel anisotropic magnetoresistance in magnetic tunnel junctions using FeAlSi

Abstract

We fabricated magnetic tunnel junctions (MTJs) with FeAlSi free layers and investigated the tunnel magnetoresistance (TMR) properties at low temperature. We observed TMR ratio increase with temperature decrease, and confirmed the TMR ratio of 179.9% at 10 K. The conductance dependence on bias voltage was measured, and a clear peak at low bias voltage similar to Fe/MgO/Fe MTJs was observed. This behavior can be explained by considering the majority band of Fe(001), and Δ5 electrons tunneling in FeAlSi/MgO/CoFeB MTJs at low bias voltage. We also investigated tunnel anisotropic magneto-resistance (TAMR) and clearly observed a TAMR peak similar to Fe/MgO/Fe MTJs, where the TAMR ratio of FeAlSi/MgO/CoFeB MTJs was 1.0% comparable to 1.1% in Fe/MgO/Fe MTJs. We concluded that electron tunneling was caused by the interfacial resonance states originating from spin orbit coupling in the FeAlSi/MgO/CoFeB MTJs.