Three Dimensional Analytical Head Field Model of a Perpendicular Recording Head

We previously described a simple, analytical three-dimensional head field model of a perpendicular recording head with a soft magnetic underlayer. In that model, we assumed the presence of two magnetically charged planes to obtain the head field at the region close to the head, surface and under the pole tip. For simplicity of calculation, the charge distribution was approximated by a step function. However, it was found that the field can be obtained analytically from a charge distribution given by a+1/(b-cx²) more accurately than from a step function approximation. In this paper, the derivation of the modified method is explained, and head fields obtained by the modified model are compared with those of the previous model and with large-scale experimental results. The modified model gives smoother head fields and better agreement with large-scale experimental results than the previous model.