We investigate the stability of magnetization in free layer where the spin torque is induced by the spin Hall effect.In terms of the Landau–Liftshitz–Gilbert equation,we find the low-energy and high-energy equilibri...We investigate the stability of magnetization in free layer where the spin torque is induced by the spin Hall effect.In terms of the Landau–Liftshitz–Gilbert equation,we find the low-energy and high-energy equilibrium states,as well as the saddle points.The stability region is defined in the phase diagram spanned by the current density and the spin Hall angle.The spin Hall effect makes the previous saddle point into a stable state above a critical current.However,in the presence of magnetic field,the spin Hall effect leads to the opposite changes in the stable regions of the two low-energy states.展开更多
In the field of ultrafast magnetism,i.e.,subpicosecond or femtosecond time scales,the dynamics of magnetization can be described by the inertial Landau-Lifhitz-Gilbert equation.In terms of this equation,the intrinsic ...In the field of ultrafast magnetism,i.e.,subpicosecond or femtosecond time scales,the dynamics of magnetization can be described by the inertial Landau-Lifhitz-Gilbert equation.In terms of this equation,the intrinsic characteristics are investigated in detail for the theoretical limit of the magnetization reversal field.We can find that there is a critical value for the inertia parameterτ_(c),which is affected by the damping and anisotropy parameter of the system.When the inertial parameter factorτ<τ_(c),the limit value of the magnetization reversal field under the ultrafast magnetic mechanism is smaller than that of the fast magnetic mechanism.Whenτ>τ_(c),the limit value of the magnetization reversal field will be larger than the limit value under the fast magnetic mechanism.Moreover,it is important to point out that the limit value of the magnetization reversal field under the ultrafast magnetic mechanism decreases with the increasing inertial factor,asτ<τ_(c)/2,which increases with inertial factorτasτ>τ_(c)/2.Finally,with the joint action of damping and anisotropy,compared with fast magnetism,we find that the limit value of the magnetization reversal field has rich variation characteristics,i.e.,there is not only a linear and proportional relationship,but also an inverse relationship,which is very significant for the study of ultrafast magnetism.展开更多
基金the Program of State Key Laboratory of Quantum Optics and Quantum Optics Devices of Shanxi University of China(Grant No.KF202203)。
文摘We investigate the stability of magnetization in free layer where the spin torque is induced by the spin Hall effect.In terms of the Landau–Liftshitz–Gilbert equation,we find the low-energy and high-energy equilibrium states,as well as the saddle points.The stability region is defined in the phase diagram spanned by the current density and the spin Hall angle.The spin Hall effect makes the previous saddle point into a stable state above a critical current.However,in the presence of magnetic field,the spin Hall effect leads to the opposite changes in the stable regions of the two low-energy states.
基金Project supported by the National Natural Science Foundation of China (Grant No.61774001)the Program of State Key Laboratory of Quantum Optics and Quantum Optics Devices,Shanxi University,China (Grant No.KF202203)+1 种基金the NSF of Changsha City (Grant No.kq2208008)the NSF of Hunan Province (Grant No.2023JJ30116)。
文摘In the field of ultrafast magnetism,i.e.,subpicosecond or femtosecond time scales,the dynamics of magnetization can be described by the inertial Landau-Lifhitz-Gilbert equation.In terms of this equation,the intrinsic characteristics are investigated in detail for the theoretical limit of the magnetization reversal field.We can find that there is a critical value for the inertia parameterτ_(c),which is affected by the damping and anisotropy parameter of the system.When the inertial parameter factorτ<τ_(c),the limit value of the magnetization reversal field under the ultrafast magnetic mechanism is smaller than that of the fast magnetic mechanism.Whenτ>τ_(c),the limit value of the magnetization reversal field will be larger than the limit value under the fast magnetic mechanism.Moreover,it is important to point out that the limit value of the magnetization reversal field under the ultrafast magnetic mechanism decreases with the increasing inertial factor,asτ<τ_(c)/2,which increases with inertial factorτasτ>τ_(c)/2.Finally,with the joint action of damping and anisotropy,compared with fast magnetism,we find that the limit value of the magnetization reversal field has rich variation characteristics,i.e.,there is not only a linear and proportional relationship,but also an inverse relationship,which is very significant for the study of ultrafast magnetism.
