Resistive switching and electric field control of ferromagnetism in SnO2 films deposited at room temperature

Abstract

Abstract The SnO2 film deposited at room temperature (RT) on the substrate of Pt/Ti/SiO2/Si is nano-crystallized, which exhibits room temperature ferromagnetism (FM) due to the oxygen vacancies of SnO2 film. The bipolar and multilevel resistive switching (RS) can be observed in the Ta/SnO2/Pt devices, where SnO2 film was deposited at RT. The Ta/SnO2/Pt device has a large ON/OFF ratio (27000) and multilevel RS, which is of great significance for high-density data storage applications. The saturation magnetization of Ta/SnO2/Pt/Ti/SiO2/Si (Ta/SnO2/Pt device) is almost the same as SnO2/Pt/Ti/SiO2/Si, which implies that the influence of Ta top electrodes on the saturation magnetization of Ta/SnO2/Pt/Ti/SiO2/Si is much less. The Ta/SnO2/Pt device shows the non-volatile and reversible saturation magnetization modulation between low resistance state (LRS) and high resistance state (HRS), which results from the formation/rupture of oxygen vacancy filaments. The saturation magnetization at LRS is higher than that at HRS. In addition, the saturation magnetization also enhances with an increase the magnitude of positive DC sweeping voltage. Without DC loop current, the saturation magnetization of Ta/SnO2/Pt increases with an application of positive electric field and drops again with an application of certain negative electric field. The saturation magnetization of Ta/SnO2/Pt can be reversibly modulated in non-volatile by only electric voltage without DC loop current. Such modulation of Ms by only electric voltage without loop DC current is connected with the change in Vo+ density in a certain range of SnO2 films.