Disentangling nucleation and propagation of magnetization reversal in exchange-biased thin films

Understanding how exchange bias (EB) --- an effect utilized in many spintronic devices -- affects basic magnetization reversal processes like domain nucleation and propagation is important both fundamentally and practically. Here, the authors describe a way to disentangle the EB field for domain nucleation and propagation in thin films. They find that nucleation EB can be quite varied, in contrast to propagation EB, and the two can differ significantly. Among other consequences, this can lead to hysteresis loop asymmetry, a widely observed yet partially understood phenomenon.