Resistive Switching and Magnetism Modulation of Hfox Based Memory with Co Interlayer

Abstract

Multilayer structures of Cu/HfOx/Co/HfOx/Pt RRAM with different Co thicknesses were prepared to investigate the resistive switching behaviors and magnetic properties. The chemical composition and oxygen vacancy of the prepared films were analyzed using XPS technology. Compared with HfOx sample, smaller switching voltage can be obtained for HfOx/Co/HfOx samples, especially for HfOx sample with 4 nm Co interlayer which also behaved better uniformity. In addition, owing to the stronger coupling effect of electrons between oxygen vacancies and Co ions, the thicker the Co thickness, the higher saturation magnetization (Ms) can be observed for HfOx/Co/HfOx samples. The Ms values at the low resistance state was always higher than that at the high resistance state due to more oxygen vacancies existed at low resistance state, and the magnetic change rate can be as high as 51%. The results indicated that appropriate Co interlayer can effectively control the formation of oxygen vacancy filaments by modulating the defect concentration near the HfOx/Co interface. A physical model of oxygen vacancy conductive filaments is utilized to illustrate the co-existence of resistive and magnetic properties in HfOx-based RRAM. The results can provide a guidance for the development of magnetoelectric multifunctional memory.

Keywords: Resistive switching, Oxygen vacancies, Filaments, Magnetoelectric memory