MICROMAGNETICS OF GMR SPIN-VALVE HEADS

Three-dimensional micromagnetic modeling of shielded giant magnetoresi stive heads with a spin-valve sensor is presented. ff the pinning fiel d from the exchange layer is not large enough, partial unsaturation of the pinned layer occurs upon excitation from the medium, which may ca use down-track output noise. Increasing the pinning strength diminishe s the playback instability, however, a larger sensor height is then de sirable for the ease of proper biasing, but at the expense of on-track signal level. The free layer magnetization is nominally horizontal, r educing off-track asymmetry compared to heads with smaller sensor heig ht.