Low-temperature quantum correction to anisotropic magnetoresistance in Tm3Fe5O12/Pt heterostructures

Spin transport in ferromagnetic insulator/heavy metal heterojunctions has attracted much attention because of its rich physics and potential applications. Here, we report an anomalous anisotropic magnetoresistance (AMR) at low temperature in a ${\mathrm{Tm}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}\text{/Pt}$ bilayer, which has often been neglected for its weak signal compared with spin Hall magnetoresistance. In our study, the magnetic proximity effect is weak above 50 K so that the AMR signal is mainly caused by ordinary magnetoresistance and spin-related scattering. However, at low temperatures, the AMR changes dramatically due to the weak localization (WL) and weak anti-localization (WAL) related to the quantum diffusion mechanism. Moreover, the dominated mechanism changes from WL to WAL in a Cu-inserted structure of TmIG/Cu/Pt without the magnetic proximity exchange coupling at the interfaces, accompanied by an AMR variation from negative to positive. Our study reveals the quantum correction effect on the AMR, which provides a possible explanation of the complex resistive behavior at low temperatures.