Switching simulations in perpendicular media: spin-wave instabilities

We have simulated the switching process in a perpendicular medium, using a simple model of a monopolar head, and visualized it by plotting the magnetizations of computational cells as a swarm of points on the time-varying contour plot of the Stoner-Wohlfarth energy. This viewpoint clarifies the spin-wave instability that leads to switching. We find that the exchange interaction leads to energy flow and, hence, energy dispersion within a grain, leading to incoherence and switching.