Tunable anomalous Hall effect in Pt/ferrimagnetic insulator bilayer

Abstract

Ferrimagnetic insulators (FMIs) are regarded as promising candidates for magnonic devices. Nevertheless, unraveling the origin of anomalous Hall effect (AHE) and tuning AHE in heavy metal (HM)/FMI prove challenging as charges exclusively traverse within the HM. Here, we investigate AHE in a Pt/Gd3Fe5O12 (GdIG) bilayer at various temperatures and observe a signal inversion at 180 K. By varying the thickness of GdIG and Pt, we note that AHE signal inversion occurs in all instances except when the Pt thickness is below 3 nm. Moreover, the monotonic variation in the temperature dependence of the coercive field (Hc) indicates that the inversion of the AHE signal is not correlated with the compensation temperature (Tc). Instead, it is attributed to the competition between spin Hall magnetoresistance (SMR) and the magnetic proximity effect (MPE). Furthermore, the precise control over the AHE inversion has achieved through the application of extra in-plane magnetic fields (Hx). Our study clarifies the origins of the AHE in Pt/FMI bilayers, where the interaction between the SMR and MPE governs the direction and magnitude of the AHE. Furthermore, we showcase the ability to control the inversion of the AHE signal by manipulating the extra Hx.