Thermal stability of SOT-MTJ thin films tuning by multiple interlayer couplings

Abstract

Abstract We investigated the thermal stability of spin orbit torque magnetic tunnel junction (SOT-MTJ) thin films by tuning multiple interlayer couplings among synthetic anti-ferromagnetic layer (SAF), reference layer, and free layer. We find that the bridge layer (here we use W) can influence the thermal stability of perpendicular magnetic anisotropy (PMA) in all the magnetic layers through the interlayer couplings. Increasing the thickness of bridge layer decouples the SAF and reference layer, resulting in higher PMA of SAF layer and lower PMA of reference layer. The reference layer further adjusts the PMA of free layer by orange-peel coupling via the tunneling barrier layer MgO such that we find another way to optimize the anisotropy without changing ferromagnetic layers. This work is helpful for engineering the interlayer coupling of SOT-MTJ thin films to achieve SOT devices with high thermal stability.