Measurements and self-consistent calculations of the magnetic fields near a perpendicular medium

Several models used to describe magnetic fields from perpendicular media and heads have been evaluated with the high-resolution field measurement system. Perpendicular fringing fields near statically written magnetization patterns were computed using an iterative self-consistent technique utilizing a hyperbolic-tangent and a Stoner-Wohlfarth hysteresis model. The fields predicted by both theories were compared with those measured from magnetization patterns statically written in two different Co-Cr media with a ring head and a single-pole head where the media had either been presaturated or demagnetized. The field distributions predicted by both theories were in generally good agreement with the measurements; the theoretical amplitudes were within 20 percent for the hyperbolic-tangent model, but significantly larger amplitude errors were found for the Stoner-Wohlfarth model. Write fields were measured from a ring head and a single-pole head, and a theory for each of the heads was shown to be in excellent agreement with the measurements.