Tuning of current-induced effective magnetic field through Rashba effect engineering in hybrid multiferroic structures

Abstract

Current-induced effective magnetic fields offer a new pathway through spin orbit interaction (SOI) to switch magnetization and have recently attracted great interest. In the conventional heavy metal/ferromagnetic metal/oxide (HM/FM/Oxide) structure, significant efforts have been made to study the role of the HM in determining effective magnetic fields. However, very little attention has been paid to the oxide layer and its interface with FM, where the Rashba effect may affect the effective field. In this report, we present a pathway to tune the effective magnetic field by engineering the Rashba effect in a hybrid multiferroic multilayer structure. A ferroelectric oxide of BaTiO₃, whose polarizations either up or down are controlled by interface engineering, was introduced into the conventional SOI multilayer with the structure of BaTiO₃/CoFeB/Pt. The current-induced effective magnetic fields increase by more than 200% when the ferroelectric polarization of BaTiO₃ changes from up to down. The changes in the effective magnetic field are mainly attributed to the different Rashba effective fields induced by the opposite ferroelectric polarizations. Our study offers a new path towards controlling the current-induced effective magnetic field and may pave the way for integrating other functional oxides into the spintronic devices.