Bias-dependent two-phase anisotropy in magnetoresistance of a GaMnAs-based magnetic tunnel junction

Abstract

Abstract We report unique two-phase anisotropy in the tunnel magnetoresistance (TMR) of a GaMnAs-based magnetic tunnel junction, obtained by investigating the magnetic-field-direction dependence with various applied bias voltages. The TMR shows two-fold symmetry about the [ 1 ¯ 10 ] axis at a low bias voltage, while at higher bias voltages, it shows four-fold symmetry about the 〈100〉 axis in the large magnetic field H region. Considering modified Jullière’s model and multiple bands with different anisotropic features, we can well reproduce the experimental TMR characteristics. Our results will lead to novel functionalities using TMRs with different symmetries in multi-orbital materials.