A micromagnetic model of metal-evaporated tape

A 3D micromagnetic model of metal-evaporated tape has been developed to represent the granular nature of the film. The model simulates the columnar structure of ME tape by fitting together columns of spherical grains whose radii have been generated from a log-normal distribution. It is demonstrated that for high exchange coupling there is a high degree of co-operative reversal in the columns; whereas for little or no exchange coupling reversal is by incoherent rotation. For high exchange coupling co-operative reversal causes regions of flux closure due to strong demagnetising fields.