Thin film magnetic head, head gimbal assembly, and hard disk drive

摘要

A longitudinal bias magnetic field control layer applies a counter bias magnetic field to a soft magnetic layer that is antiparallel (in opposite direction) to a longitudinal bias magnetic field. A magnitude of the counter bias magnetic field applied to the soft magnetic layer by the longitudinal bias magnetic field control layer is set smaller than that of the longitudinal bias magnetic field at a track center portion of the soft magnetic layer applied by a pair of bias magnetic field applying layers. A substantial longitudinal bias magnetic field is substantially applied to the soft magnetic layer in the same direction as that of the longitudinal bias magnetic field, and a magnitude of the substantial longitudinal bias magnetic field is maximum at both end portions of the soft magnetic layer and is weakened at the center portion of the soft magnetic layer.