Multi-step nucleation of magnetic domains

Magnetic domain nucleation is one of the central topics in magnetism and spintronics, with its detailed mechanism having been a subject of ongoing debates. Here, we show that magnetic domain nucleation can be described by a multi-step thermal activation process, in contrast to the conventionally assumed single-step process. We also demonstrate that the temporal sequence of nucleation across multiple nucleation sites can be actively manipulated by both magnetic field and ion irradiation. These results are expected to advance our understanding of magnetic domain nucleation and provide a viable method for designing and controlling spintronic devices based on multiple nucleation sites.