Sign reversal of twofold angle-dependent magnetoresistance in Pt/Mn4N bilayers

Abstract

Ferrimagnetic Mn4N thin films with perpendicular magnetic anisotropy show great potential for spintronic applications. In this study, we systematically investigated the angle-dependent magnetoresistance (ADMR) of epitaxial Mn4N thin films and Pt/Mn4N bilayers. In the Pt/Mn4N bilayer, interfacial spin Hall magnetoresistance (SMR) dominates the room-temperature twofold ADMR. With decreasing temperature, the Pt/Mn4N bilayer exhibits a sign reversal of the twofold ADMR due to competition between the anisotropic field-induced magnetoresistance (FIMR) of the Mn4N layer and the interfacial SMR, indicating a transition from interface- to bulk-dominated magnetotransport properties. ADMR measurements on Mn4N films confirm that the anisotropic FIMR contributes a non-negligible twofold component to the ADMR. This work enhances our understanding of the competing magnetotransport mechanisms in Pt/Mn4N bilayers, thereby providing a foundation for spintronics based on antiperovskite nitrides.