An eddy-current and micromagnetism model with applicationsto disk write heads

As data rates increase and the size of the disk write head decreases it is likely that a standard non-linear eddy-current simulation of a disk write head will not fully capture dynamic effects. In this paper we propose a coupled eddy-current and micromagnetics model for the disk write head. We present a simple finite difference formulation derived from a mass-lumped finite element method. This derivation allows us to verify that, before time discretization, the semi-discrete scheme obeys the same energy decay equality as the partial differential equation model. We show some numerical results for an ‘academic’ disk writer model