Controlling Bubble and Skyrmion Lattice Order and Dynamics via Stripe Domain Engineering in Ferrimagnetic Fe/Gd Multilayers

ABSTRACT Ferrimagnetic Fe/Gd multilayers host maze‐like stripe domains that transform into a disordered bubble/skyrmion lattice under out‐of‐plane magnetic fields at ambient temperature. Femtosecond magneto‐optics distinguishes these textures via their distinct coherent breathing dynamics. Crucially, applying a brief in‐plane “set” magnetic field to the stripe state enhances both frequency and amplitude of the bubble/skyrmion lattice breathing mode. Lorentz transmission electron microscopy, magnetic force microscopy, and micromagnetic simulations reveal that this enhancement arises from field‐aligned stripes nucleating a dense, near‐hexagonal bubble/skyrmion lattice upon out‐of‐plane field application, with strong indications for a pure skyrmion lattice. Thus, modifying the initial domain configuration by in‐plane fields enables precise control of coherent magnetization dynamics on picosecond to nanosecond timescales and potentially even of topology.