Voltage Control of Perpendicular Magnetic Anisotropy by Resistive Switching through a Ta/HfO2 Bilayer

Voltage control of perpendicular magnetic anisotropy (VCPMA) by resistive switching (RS) is an approach for manipulating perpendicular magnetization, which is of significant importance in realizing energy-efficient and high-speed spintronic devices. However, simultaneously achieving good RS performance and effective VCPMA poses a considerable challenge. In this study, we investigated the VCPMA in the RS device with a stack of Pt/Co/Ta/HfO2/Pt. With the aid of Ta's strong oxygen affinity and the high mobility of oxygen ions in the resultant Ta-oxide layer, the insertion of an appropriately thick Ta layer can not only improve the RS performance but also modulate the PMA effectively. When a negative voltage is applied and increased to the "set" voltage, oxygen ions may migrate from the HfO2 layer to the Ta layer, resulting in a transition from the high resistance state (HRS) to the low resistance state (LRS) and a weakening of PMA as well. On the contrary, when a positive voltage is applied and increased to the "reset" voltage, oxygen ions will return to the HfO2 layer, leading to the device switching from LRS to HRS and partial recovery of PMA. This work provides a clue to the design of energy-efficient spintronic devices.