Study On The Influence Of Interface Effect Between HM And MgO On Spin Transport In Magnetic Heterostructures

One of the goals of the development of spintronics is to bring spin degrees of freedom into traditional electronic devices,expecting to use spin to replace the position of charge in information recording and processing,and to build a new generation of information storage and computing principles and devices.Magnetic heterostructure is a composite structure composed of magnetic metal or magnetic insulator and nonmagnetic metal(NM),which can generate and detect spin flow at the same time.It is not only an ideal system for studying the phenomena related to spin transport,but also the core component for the functionalization of various spintronic effects.In order to further highlight the function of spintronics-related effects,the magnetic heterostructure is getting thinner and thinner,so the interface effect is becoming more and more significant.Due to the inherent symmetry breaking of the interface,the new phenomena produced by the interface under the action of spin-orbit coupling continue to expand people's understanding in the field of spintronics.In this paper,the spin orbit coupling effect of HM(Pt and Ta)/Mg O interface is studied.By means of spin Hall magnetoresistance,spin pump effect and spin torque ferromagnetic resonance,the effect of Mg O cover layer on the generation and transport of spin flow in CoFeB/HM heterostructure is studied systematically.the main conclusions are as follows:1)the MgO coating layer enhances the diffusion of HM atoms into CoFe B,resulting in the increase of CoFeB dead layer thickness.The interface anisotropy weakens and the spin pumping effect is weakened at the same time.Moreover,the easier the diffusion of HM atoms into the CoFeB,the more the Mg O coating layer enhances the diffusion process.2)It is verified that the Rashba-Edelstein effect exists at the HM/Mg O interface,that is,the charge current produces spin accumulation at the HM/Mg O interface.This effect leads to spin-orbit magnetoresistance in CoFeB/HM/Mg O heterostructures,and additional spin-orbit torque can be applied to CoFeB when the HM layer is thin.At the same time,the intensity of the effect is regulated by the HM,but the interfacial spin accumulation induced by the effect has the same polarization direction.