Orbital current induced angular-dependent magnetoresistance in Mn4N/Ti bilayers

Abstract

The detection of orbital currents in ferromagnetic/light-metal bilayer systems has remained a challenging task in recent studies. In this work, Mn4N epitaxial thin films and Mn4N/Ti bilayers with perpendicular magnetic anisotropy were deposited on MgO (001) substrates using facing-target magnetron sputtering. When the magnetic field is rotated in the plane perpendicular to the direction of the current, the Mn4N/Ti bilayers exhibit a negative angular-dependent magnetoresistance compared to the Mn4N thin films. Moreover, this phenomenon is suppressed when a Pt interlayer is introduced. We attribute this phenomenon to the orbital current generated via the orbital Hall effect and the orbital Rashba effect at the interface, which interacts with the magnetization orientation to modulate the electrical resistance. These results provide circumstantial evidence that implicates the generation of orbital currents in Ti and their potential role in the interfacial magnetotransport phenomena.