Magnetization reversal dynamics with submicron-scale coercivity variation in ferromagnetic films

We report experimental evidence that submicron-scale local coercivity variation determines magnetization reversal dynamics in ferromagnetic thin films. Local coercivity distribution is generated from a two-dimensional array of hysteresis loops each of 0.32X0.32 mu m(2) spots simultaneously measured using a magneto-optical microscope magnetometer. We directly demonstrate that domain reversal pattern is truly coincident with local coercivity variation. Local switching time of domain evolution is found to be exponentially dependent on local coercivity governed by a thermally activated relaxation process.