Research Of Spin Pumping Effect In Multilayer With Exchange Bias

Pure spin current,transmitting directionally spin angular momentum in material,becomes not only the core of the new physical effects in the spintronics but also the main media achieving the reversal of the local spin(or magnetic moment)in the next generational magnetic storage and processing devices.Obviously,the studies on the physical properties of the pure spin current and the microscopic mechanism of the interaction between the pure spin current and the material are critical in the spintronics.The spin pumping effect is a main experimental method to obtain the pure spin current,and the effective spin mixing conductance(?)characterizes the injective efficiency of the pure spin current in the spin pumping effect.However,there isn't a clear physical image of the effective spin mixing conductance,which is an intrinsic parameter depending on the texture of the interface.So,the researches of(?)in the interface with different texture would contribute to the physical explanation of(?).Above,this paper takes the interface ferromagnetic/antiferromagnetic(FM/AMF)with exchange bias coupling as the study object,and explores the effective spin mixing conductance and spin torque(ST)effect in FM/AMF by using spin-torque ferromagnetic resonance(ST-FMR).The main innovative conclusions are as follows:1.We found that the orientation of the microscopic magnetic moments in the interface could give an effect to(?),and the exchange spring effect in FM/AMF could achieve the adjustment of the injective efficiency of the pure spin current.We discover an anisotropy,depending on the relative angle between the directions of the applying field and the exchange bias field,of the Gilbert damping constant obtained by ST-FMR in FM/AMF,that owes to the interaction between the pure spin current and the exchange spring formed by the exchange bias field in the interface of FM/AMF.Therefore,the effective spin mixing conductance as a function of the Gilbert damping constant would present a similar anisotropy.Above,the orientation of the applying field which could control the exchange spring status could adjust the injective efficiency of the pure spin current.2.We could control the texture of the ST via FM/AMF interface with the pinning of AFM.We obtain the rectification line shape of the FM/AFM/NM system via ST-FMR,and explore the character of the ST via the line shape depending on the angle.We find that not only the Damping-like torque with the in-plane spin polarization,which is similar to the general one in FeNi/Pt system,but also the new Field-like torque and Damping-like torque with the spin polarization along z axis appear in FM/AFM/NM.Besides,we also obtain the dependences between the character of the ST and the direction of the exchange bias field.