Modulated spin orbit torque in ultrathin ferromagnetic layer with different capping layers

In heavy metal (HM)/ferromagnetic metal (FM)/oxide heterostructures with perpendicular magnetic anisotropy (PMA), the magnetization can be efficiently controlled through spin orbit torque (SOT), which has attracted great attention since its applications in spintronic devices. In this work, we have investigated the SOT with modifying capping layers X in Pt/Co/X trilayers. In these systems, both the bottom Pt/Co and top Co/X interfaces are utilized to generate SOT via bulk SHE effect and/or Rashba effect. By the selecting of different capping layer X, one can expect an enhancement or cancellation of SOT contributions via interface effect, which provides an interesting prospect for enhancing the efficiency of SOT through a proper combination of materials in the structural engineering. Our experimental study explored the choice of the capping materials which influenced the magnetic behavior and current-induced magnetization switching process.