THE STUDY OF PERPENDICULARLY MAGNETIZED COFE/PD MULTILAYERS FOR DOMAIN WALL MOTION

Abstract

We focus the studies of DW motion in a CoFe/Pd multilayer-based nanowire with strong PMA. We find that high PMA, low saturation magnetization, narrow DW width and high spin polarization can induce low threshold current density for DW motion in CoFe/Pd superlattice-like multilayer films. Next, we show that DW motion can be driven by a low Jth with small bias field in the CoFe/Pd multilayers-based nanowires. The combination of non-adiabatic spin-transfer-torque and spin orbit torque generated by Ta layer is found to be the main contribution to the current induced DW motion. We further fabricate the perpendicularly magnetized nanowires based on the CoFe/Pd superlattice-based SAF structure. A minimum Jth = 0.92×10¹&sup1 A/m² and a maximum v = 150 m/s under a driving current density J = 1.5×10¹² A/m² for DW motion are observed, which can be attributed to the exchange coupling torque (ECT) generated in the SAF structure.