  Magnetic trilayers having large perpendicular magnetic anisotropy (PMA) and
high spin-orbit torques (SOTs) efficiency are the key to fabricate nonvolatile
magnetic memory and logic devices. In this work, PMA and SOTs are
systematically studied in Pt/Co/Cr stacks as a function of Cr thickness. An
enhanced perpendicular anisotropy field around 10189 Oe is obtained and is
related to the interface between Co and Cr layers. In addition, an effective
spin Hall angle up to 0.19 is observed due to the improved antidamping-like
torque by employing dissimilar metals Pt and Cr with opposite signs of spin
Hall angles on opposite sides of Co layer. Finally, we observed a nearly linear
dependence between spin Hall angle and longitudinal resistivity from their
temperature dependent properties, suggesting that the spin Hall effect may
arise from extrinsic skew scattering mechanism. Our results indicate that 3d
transition metal Cr with a large negative spin Hall angle could be used to
engineer the interfaces of trilayers to enhance PMA and SOTs.
