Study On Current Driven Magnetization Switching Under Non-collinear Spin Hall Angle

At present,how to effectively control the magnetic moment in the zero magnetic field is one of the important research contents in the field of spintronics,and the current driven magnetization switching through the effect of spin orbit torque(SOT)is an important method to realize this control.Therefore,it is very important to understand the physical properties of current-spin current conversion.In the traditional SOT system,for example,when an in-film current is applied to the heavy metal/magnetic material film,the heavy metal layer will generate spin current or spin accumulation which is perpendicular to the direction of the current due to the spin-orbit coupling effect,thus realizing the regulation of the magnetic moment of the magnetic layer.Recently,it has been discovered that an unconventional situation may occur when the symmetry is broken,that is,there are multiple polarization directions in the spin current generated.The effective spin Hall Angle is the ratio of the spin current to the current.For the spin current with multiple spin polarization directions,the corresponding spin Hall Angle is the non-collinear spin Hall Angle mentioned in this paper.The current with non-collinear spin hall Angle will produce unconventional spin orbit torque,so the current induced spin orbit torque can be effectively regulated and switching in magnetization switching.In this paper,we use micromagnetic simulation to study the current driven magnetization switching in the spin source layer with multiple spin polarized spin currents.In the micromagnetic simulation,we consider the current induced Rashba-like spin polarization(S_y),Dresselhaus-like spin polarization(S_x)and out-of-plane like spin polarization(S_z)spin currents,and the magnetization reversal simulation of the non-collinear spin transfer moment.The main work is as follows:The multilayer structure of NM/FM/Oxide was simulated,in which Nm was used as the spin source layer,Oxide was used as the Oxide covering layer and Fm was used as the ferromagnetic free layer.The ratio of the components of the spin current in different polarization directions is described in the form of the ratio and of the spin torque,and the relationship between the critical overturning current and the polarization ratio is studied by changing the current at different ratios.The ratio of the components of spin current in different polarization directions is described in the form of spin torque ratio,/,and,/_,,and the relationship between the critical switching current and the polarization ratio is studied by changing the current at different ratios.The results show that the current induced spin polarization can effectively contribute out-of-plane damping like torque,so as to realize the m_zswitching in the zero magnetic field.Similarly,the current induced Dresselhaus-like spin torque can switching m_x.Our results may provide a new perspective for understanding the current induced SOT magnetization rollover induced by spin sources with non-collinear spin Hall angles,and provide a new idea for potential applications of spintronic devices.