Study of spin-orbit torque induced magnetization switching in synthetic antiferromagnet with ultrathin Ta spacer layer

Spin manipulation in magnetic materials based on spin-orbit torque gives rise to promising families of magnetic memory and logic devices. In the synthetic antiferromagnetic structure of CoFeB/Ta/CoFeB where both CoFeB layers exhibit perpendicular anisotropy, we study the magnetization switching process based on the mechanism of spin-orbit torque and interlayer exchange coupling mediated by a Ta layer. The magnetization switching trigged by in-plane current is achieved. Though the heavy metal Ta layer is ultrathin, the critical current density is 8 x 10(6)-1 x 10(7) A/cm(2) with a bias field of 5-10 mT. Meanwhile, the current induced anti-damping-like field and field-like field are determined by the harmonic lock-in technique. Harmonic results suggest that the generation efficiency of the field-like field is similar to 1.24 times that of the anti-damping-like field. The effective spin Hall angle of a Ta layer is derived to be around 0.158. Finally, we examine the magnetic properties of CoFeB layers as a function of temperature which indicates that the magnetic properties of bottom and top CoFeB layers have a close correlation with the interface quality and growth order. Published by AIP Publishing.