Tailoring of Creep Regime Domain Wall Dynamics in Perpendicularly Magnetized Pd/Co/Pd Trilayers

Understanding magnetic domain wall (DW) dynamics is vital for improvingthe performance of heavy metal/ferromagnet based spintronic devices.Pd/Co/Pd multilayers hosting perpendicular magnetic anisotropy andinterfacial Dzyaloshinskii-Moriya interaction are prototypes for high densitymagnetic memory devices. This work presents the creep regime DWdynamics in Pd/Co/Pd trilayers with Ta buffer layer excited by symmetricfield-induced domain wall motion using Kerr microscopy. A systematicincrement of DW velocity with increasing Co thickness is observed.SQUID-VSM measurements reveal that the effective anisotropy constantdecreases with the Co layer, leading to an increased DW width. Kerrmicroscopy images confirm that the DW is becoming rougher with magneticlayer thickness because of the dominance of magnetostatic energy over theDW energy. Hard X-ray photoemission spectroscopy (HAXPES) reveals thepresence of alloying at interfaces of Co/Pd. The asymmetry in magneticcircular dichroism HAXPES at the Pd 3d edge pictures the induced magneticmoment in Pd which is consistent with the larger saturation magnetizationobtained from vibrating sample magnetometry. Extended X-ray absorptionfine structure performed in out-of-plane and in-plane geometry shows thedisordered nature of the Co local environment with the interdiffusion of Pdatoms into Co causing an asymmetry in the bonds.