Analytic spectral response functions for two-dimensional models of perpendicular recording heads

This paper discusses the spectral response functions of various head geometries in perpendicular magnetic readback from a double layer medium. New analytic expressions, based on idealized two-dimensional models, for the spectral response of a symmetrically shielded constant potential pole and a thin film head with either constant or linearly varying pole potential are presented. The spectral response function for a single pole with an arbitrary magnetic potential distribution, varying through the pole thickness only, is also given. Specific examples are discussed in conjunction with related linear dibit shift results. The analysis indicates that certain graded magnetization single poles may have superior readback capabilities in comparison with conventional ring, single pole, or thin film heads, especially for "in contact" recording. It appears that a single pole with a cosine-squared magnetization may have almost identical replay characteristics to a symmetrically shielded pole.