Study On Spin-Orbit Coupling In Ferromagnetic/Heavy Mental Structure And Synthetic Antiferromagnetic

Spintronics as a subject of manipulating the spin freedom of the electron based on traditional electronics has attracted a great deal of attentions due to its advantages of fast reading/writing speed,lower power consumption,and nonvolatility for spin-based devices.Its major application in the field of magnetism is employing Spin Hall Effect?SHE?and interfacial Rashba Effect with respect to the Spin-Orbit Coupling?SOC?effect of heavy metal,transforming the charge current into spin current to generate the Spin-Orbit Torques?SOTs?to manipulate the magnetic moment.In this paper,we have studied the spin orbit torques of Pt/Co/SmO_x/Ta system and unidirectional spin hall magnetoresistance of synthetic antiferromagnetic Ta/CoFe/Ru/CoFe/Pt system.Our conclusions have been described as follows:1.current and temperature dependence of spin-orbit torques in perpendicularly magnetized Pt/Co/SmO_x/Ta heterojunction by using harmonic Hall voltage measurement setup have been studied in this thesis.The results show that the magnetization switching could be achieved with a lower current density of 1.26×10⁶A/cm².Furthermore,the damping-like torque increased from 2.01×10^-6 Oe/(A·cm^-2)to 4.3×10^-6 Oe/(A·cm^-2)with increasing the temperature from 100 K to 400 K.However,the field-like torque has no significant changes.We have ascribed this temperature dependence to the influence of temperature on resistivity of Pt and nonequilibrium proximity effect.2.the angle dependences of longitudinal(R_xx)and transverse?R_H?magnetoresistance in synthetic antiferromagnetic Ta/CoFe/Ru/CoFe/Pt system studied in this thesis,using the physical properties measurement set?PPMS?and other ourselves-established measurement setup.Finally,the relationships between the temperature and R_xx show the AMR increases with temperature increasing,due to the bated role of lattice scattering and heat disturbance at lower temperature,In other words,the electron-magnon scattering plays a dominated role at lower temperature;the temperature dependence of SMR is the result of spin hall angle increases while spin diffusion distance decreases with temperature increasing.3.the first and second harmonic resistance of synthetic antiferromagnetic Ta/CoFe/Ru/CoFe/Pt system by using Harmonic Voltage measurement setup studied in this thesis.we found the variation period of the second harmonic resistance(?R_2w-y)is2p.Moreover,the results confirm that the sign of ?R_2w-y will be changed if we changed the polarity of the current and/or the direction of the magnetization,R?j,m?=-R?-j,m?=-R?j,-m?.It may be resulted by the spin-dependent scattering at CoFe/Ru and CoFe/HM interfaces,and its signal magnitude is directly related to the spin accumulation induced by spin hall effect.