Indication of stochastic photothermal dynamics around a topological defect in a chiral magnet

This is the authors' abstract. We don't add key points for this paper.

Chiral magnets host topologically protected spin textures whose nonequilibrium dynamics are crucial in phase transitions and domain evolution, yet ultrafast defect-mediated processes remain poorly understood. Here, we investigate a photothermally induced helical-to-paramagnetic phase transition in Co9Zn9Mn2 using pump–probe Lorentz transmission electron microscopy (LTEM). Following the suppression of the magnetic stripe contrast induced by femtosecond laser pulses, we observe a directional recovery process of magnetic order driven by the anisotropic thermal diffusion, toward the thick region that effectively acts as a heat sink. Remarkably, around a magnetic edge dislocation, the magnetic contrast recovery exhibits a pronounced delay accompanied by a transient blurring of LTEM contrast. These findings suggest that the recovery dynamics around the magnetic edge dislocation proceed through multiple relaxation paths that are selected stochastically. Our results indicate a possible enhancement of stochasticity around topological defects during the recovery dynamics of magnetic phase transitions.