Current induced magnetization switching in PtCoCr structures with enhanced perpendicular magnetic anisotropy and spin-orbit torques

摘要

Magnetic trilayers having large perpendicular magnetic anisotropy (PMA) andhigh spin-orbit torques (SOTs) efficiency are the key to fabricate nonvolatilemagnetic memory and logic devices. In this work, PMA and SOTs aresystematically studied in Pt/Co/Cr stacks as a function of Cr thickness. Anenhanced perpendicular anisotropy field around 10189 Oe is obtained and isrelated to the interface between Co and Cr layers. In addition, an effectivespin Hall angle up to 0.19 is observed due to the improved antidamping-liketorque by employing dissimilar metals Pt and Cr with opposite signs of spinHall angles on opposite sides of Co layer. Finally, we observed a nearly lineardependence between spin Hall angle and longitudinal resistivity from theirtemperature dependent properties, suggesting that the spin Hall effect mayarise from extrinsic skew scattering mechanism. Our results indicate that 3dtransition metal Cr with a large negative spin Hall angle could be used toengineer the interfaces of trilayers to enhance PMA and SOTs.