Ferromagnetic insulators have attracted much attention in spintronics research due to their advantages such as no ohmic loss and low damping coefficient. However, due to the fact that charges are only transferred within heavy metals, revealing the origin of the anomalous Hall effect (AHE) in heavy metal/ferromagnetic insulator heterojunctions and regulating its AHE is challenging.

Professor An Hongyu's team from the School of New Materials and New Energy at Shenzhen University of Technology studied the AHE of Pt/Gd3Fe5O12 (GdIG) heterojunction devices at different temperatures and observed signal reversal at 180K. After verification, it was found that the reversal is due to the competition between spin Hall magnetoresistance and magnetic proximity effect, and is independent of the magnetization compensation temperature. In addition, precise control of AHE inversion was achieved by applying an external and internal magnetic field, revealing the competitive mechanism between spin Hall magnetoresistance and magnetic proximity effect.

This study establishes a theoretical basis by delving into the mechanism of in-plane magnetic field regulation of AHE signal inversion, providing a reference for the future development and regulation of low-power and high-efficiency spintronic devices based on ferromagnetic insulators.

This research achievement was published as an invited manuscript in the international academic journal Applied Physics Letters under the title Tunable Anomalous Hall Effect in Pt/Ferromagnetic Insulator Bilayer. Master's student Liu Lin and undergraduate student Ye Jianxin are the co first authors of this paper. Professor An Hongyu from the School of New Materials and New Energy at Shenzhen University of Technology is the corresponding author, and Associate Researcher Yang Hui and Associate Professor Lin Liyu are the co corresponding authors.

Paper link:https://doi.org/10.1063/5.0188886

Figure 1. (a) Schematic diagram of electronic device testing, (b) Diagram of AHE resistance changing with magnetic field at different temperatures, (c) Diagram of AHE resistance changing with temperature, (d) Diagram of coercivity changing with temperature.