Micromagnetics of long ferromagnetic particles

A 3D micromagnetic model is used to examine nucleation field dependence on exchange length, particle size and external field angle for long ferromagnetic particles. Reasonable agreement is shown between the model's predictions and recent experiments on Ni particles. Illustrations of the reversal mode are included which show reversal beginning at the ends and proceeding towards the center of the particle. The amount of discretization necessary for accurate modelling is investigated. For a tape particle with a radius equal to the exchange length, a discretization along the length of the particle is found to be adequate.