Patent ID: 7142392

Claim:
A thin film head having reading part and recording part comprising: an upper magnetic pole front end layer; and a lower magnetic pole having a lower magnetic main layer, a lower magnetic pole front end portion above the lower magnetic main layer, and a projection step portion above the lower magnetic pole front end portion; wherein a length of the lower magnetic pole front end portion in a depth direction is smaller than a length of the lower magnetic main layer in the depth direction; wherein a length of the projection step portion in the depth direction is smaller than the length of the lower magnetic main layer in the depth direction; wherein a width of the lower magnetic pole front end portion in a track width direction is smaller than a width of the lower magnetic main layer in the track width direction; wherein a width of the projection step portion in the track width direction is smaller than the width of the lower magnetic pole front end portion in the track width direction; and wherein the upper magnetic pole front end layer has a magnetic pole expansion position; and wherein a length in the depth direction from an air bearing surface to the magnetic pole expansion position is less than a length from the air bearing surface to a gap depth position of the lower magnetic pole front end portion.