Light-induced bimerons in a chiral magnet

Controlled generation of topological spin textures, such as merons and their bound state, the bimerons, is essential for advancing spintronic technologies and elucidating soliton physics in condensed matter. Using in situ Lorentz transmission electron microscopy coupled with femtosecond laser pulse, we demonstrate the creation of two distinct Bloch-type bimeron states in chiral magnet Co8Zn8Mn4 thin plates at room temperature. Magnetic imaging and micromagnetic simulations reveal that bimeron density varies with applied magnetic field strength, enabling dynamic topological control. We further establish that the topological classification of laser-generated bimerons is invariant with specimen thickness. Field-driven reversible transformations between elongated and circular bimeron morphologies are observed, governed by the competition of Zeeman energy and magnetic shape anisotropy. Micromagnetic simulations quantitatively reproduce these metastable states, validating a unified meron-skyrmion topological framework. This work establishes a single-pulse protocol for optical manipulation of topological spin textures. Bimerons are magnetic solitons that are topologically equivalent to skyrmions in in-plane magnetized systems. This study demonstrates the room-temperature creation of bimerons in Co8Zn8Mn4 via femtosecond laser pulse excitation, revealing dynamic topological control and morphological transitions of these solitons.