Patent ID: 8896974

Claim:
A thin film magnetic head, comprising: a spin valve film that includes a magnetization free layer of which a magnetization direction changes according to an external magnetic field, a magnetization pinned layer that has a positive saturation magnetostriction constant and of which a magnetization direction with respect to the external magnetic field is oriented to a direction perpendicular o an air bearing surface, and a non-magnetic spacer layer that is disposed between the magnetization free layer and the magnetization pinned layer; and a pair of side layers that are disposed at both sides of the spin valve film in a track width direction and at least in the vicinity of the magnetization free layer and the magnetization pinned layer, wherein each of the side layers has a bias magnetic field application layer that includes a soft magnetic layer and applies a bias magnetic field in the track width direction to the magnetization free layer, and a gap layer that is positioned between the spin valve film and the bias magnetic field application layer, wherein the gap layer is made with a MgO layer, and the side layers have compression stresses at least in the vicinity of the magnetization pinned layer, wherein the side layer includes either one of a Ta film and a Ru film or both of the Ta film and the Ru film, being positioned between the gap layer and the bias magnetic field application layer.