Direct visualization of local magnetic domain dynamics in a 2D Van der Walls material/ferromagnet interface

Abstract

Controlling the magnetic domain propagation is the key to realize ultrafast, high-density domain wall-based memory and logic devices for next generation computing. Two-Dimensional (2D) Van der Waals materials introduce localized modifications to the interfacial magnetic order, which could enable efficient control over the propagation of magnetic domains. However, there is limited direct experimental evidence and understanding of the underlying mechanism, for 2D material mediated control of domain wall propagation. Here, using Lorentz-Transmission Electron Microscopy (L-TEM) along with the Modified Transport of Intensity equations (MTIE), we demonstrate controlled domain expansion with in-situ magnetic field in a ferromagnet (Permalloy, NiFe) interfacing with a 2D VdW material Graphene (Gr). The Gr/NiFe interface exhibits distinctive domain expansion rate with magnetic field selectively near the interface which is further analysed using micromagnetic simulations. Our findings are crucial for comprehending direct visualization of interface controlled magnetic domain expansion, offering insights for developing future domain wall-based technology.