Anomalous Hall effect in magnetic insulator heterostructures: Contributions from spin-Hall and magnetic-proximity effects
Shilei Ding, Zhongyu Liang, Chao Yun, Rui Wu, Mingzhu Xue, Zhongchong Lin, Andrew Ross, Sven Becker, Wenyun Yang, Xiaobai Ma, Dongfeng Chen, Kai Sun, G. Jakob, Mathias Kläui, Jinbo Yang
Abstract
In this letter, we study the origin of the anomalous Hall effect (AHE) in ferrimagnetic insulator ${\mathrm{Tm}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$ (TmIG)/Pt heterostructures. A monotonic decrease of the anomalous Hall resistivity ($\mathrm{\ensuremath{\Delta}}{\ensuremath{\rho}}_{\mathrm{AHE}}$) with decreasing temperature is observed for TmIG/Pt, and a sign reversal of $\mathrm{\ensuremath{\Delta}}{\ensuremath{\rho}}_{\mathrm{AHE}}$ occurs at around 80 K. With the addition of a Cu interlayer, the $\mathrm{\ensuremath{\Delta}}{\ensuremath{\rho}}_{\mathrm{AHE}}$ similarly decreases as a function of temperature, but maintains the same sign across the full temperature range. This indicates that both the magnetic-proximity effect and spin Hall effect in the TmIG/Pt bilayer contribute to the AHE signal with opposing signs. The spin-Hall contribution to the AHE is dominant at room temperature but decreases with decreasing temperature. Meanwhile, the magnetic-proximity contribution to the AHE becomes dominant with decreasing temperatures, leading to a change of sign for $\mathrm{\ensuremath{\Delta}}{\ensuremath{\rho}}_{\mathrm{AHE}}$. We exclude a dominant influence of a ferrimagnetic compensation point in the temperature region by complementary magnetic hysteresis and neutron diffraction measurements. Our work, based on a simple method, sheds light on the origin of the AHE in magnetic insulator heterostructures, where the competition between the magnetic-proximity effect and spin Hall effect governs the sign and amplitude of the AHE.