Interface engineered perpendicular magnetic anisotropy-controlled propagation of magnetic domain

Abstract

We report the impact of ferromagnetic layer thickness and stack configuration on the magnetic properties, perpendicular magnetic anisotropy (PMA), modified magnetization switching mechanisms, and creep regime domain wall (DW) dynamics, including their propagation velocity, in a Pt/CoFeB/Ru tri-layer system. An effective magnetic anisotropy Keff of (8.8 ± 0.15) × 105 erg/cm3 has been achieved without any post-annealing, highlighting the high-quality interface. The evaluation of PMA strength with ferromagnetic thickness and the number of stacks quantitatively reveals cumulative interfacial contributions that govern the overall magnetic anisotropy in the system. The deviation of the angular dependence of the magnetization switching field from the conventional Kondorsky model is well described using a phenomenological interpolation Kondorsky model, which signifies the role of field-induced domain-wall softening and pinning effects during the reversal process. Furthermore, polar-magneto optical Kerr effect microscopy imaging during the magnetization reversal process provides detailed insight into domain nucleation and the subsequent DW propagation driven by magnetic fields. The observations reveal well-defined, stable bubble magnetic domains that evolve coherently under the applied magnetic field. Our results demonstrate an effective approach for engineering interface-driven PMA and related magnetic phenomena in the heterostructures for next-generation low-power and DW-based spintronic devices.