The effects of closure domains on flux conduction in thin film recording head

Abstract

The magnetic flux conductivity in the tip of a recording head was examined for various applied field and closure domain configurations using a two-dimensional micromagnetic model developed to obtain the domain patterns in soft magnetic thin films. A permalloy thin film sample was selected to simulate a monopole head configuration, and an external field was applied to various closure domain ground states that had zero net remanence magnetization. It was found that for small fields the magnetization process is linear and reversible, and both the susceptibility and the effective track width increase as the size of the closure domains is reduced. For large fields, however, the variation of the flux conduction is much less sensitive to the size of the zero-field closure domains, since the sample is nearly saturated. Small jumps were observed in the magnetization curves corresponding to the domain wall nucleation and annihilation, which can be a source of head noise. It was also observed that the effective center of magnetic pole shifts with increasing field.