Magnetic tunnel junctions using epitaxially grown FeAlSi electrode with soft magnetic property

Magnetic tunnel junctions (MTJs) with (001)-oriented D03-FeAlSi epitaxial films, which have both soft magnetic properties and surface flatness, were fabricated and characterized. A tunnel magnetoresistance (TMR) ratio of 121% was observed, and a relatively low switching field was also confirmed, reflecting the soft magnetic property of FeAlSi. However, the results of the cross-sectional TEM image of the MTJ and the bias dependence of the TMR ratio indicate that the FeAlSi/MgO interface is probably oxidized. Therefore, since an insertion layer at the interface can suppress oxidation and further improve the TMR ratio, MTJs using FeAlSi epitaxial films are promising structures suitable for applications such as MTJ-based magnetic sensors and worthy of further investigation.