Reversal behaviour in perpendicular iron particle arrays (alumite media)

Alumite was chosen as an ideal material for investigating the influence of particle interaction on the magnetic behavior of a perpendicular anisotropic particle array. It was found that the measured reduced coercivity versus the reduced diameter curves fit the theoretical curling mode. However, the magnetic behavior will no longer obey curling if the applied field deviates from the film normal. This is due to the presence of magnetic charge next to iron single-domain cylinders, which completely destroys the validity of curling. Their reversal can be interpreted as due to the superposition of Cos-type incoherent rotation and the magnetization reversal caused by the demagnetizing field and the dipole-dipole field.>