Three-dimensional micromagnetic finite element simulations including eddy currents

We developed a micromagnetic eddy current method that allows arbitrary geometries, requires no mesh outside the ferromagnet, and uses a stable integration scheme. We simultaneously solve the Landau–Lifshitz–Gilbert equation and the quasistatic Maxwell equations using a hybrid finite element/boundary element method (FEM/BEM). The eddy current field is directly calculated from the space time behavior of the magnetization rate of change. The boundary conditions of the eddy current field at infinity are taken into account using a FEM/BEM scheme. The resulting system of differential algebraic equations is solved using a backward differentiation method.