Finite element simulation of discrete media with granular structure

Summary form only given. Discrete media show great potential for future ultra-high density magnetic recording. A possible patterning scheme is the removal of magnetic material from existing media using a focused ion beam. Patterning significantly changes the hysteresis properties. In this work we apply a hybrid finite element/boundary element method to simulate the magnetization reversal process in a perpendicular granular film, a patterned media, and a single magnetic island. We start with a continuous CoCrPt film consisting of 625 columnar grains which are obtained from a Voronoi tesselation. The grain diameter is 10 nm and the film thickness is 21 nm. In a second step, we take out elements in a grid pattern, to obtain an array of individual islands. The island size is 70 nm with a gap of 20 nm. The subsequent calculation of equilibrium states solving the Gilbert equation of motion provides the demagnetization curve.