Patent ID: 8189303

Claim:
A thin film magnetic head, comprising a magneto-resistance (MR) laminated body that has a first magneto-resistance (MR) magnetic layer with a direction of magnetization that is changed according to an external magnetic field, a nonmagnetic middle layer and a second magneto-resistance (MR) magnetic layer with a direction of magnetization that is changed according to the external magnetic field, and wherein the first MR magnetic layer, the nonmagnetic middle layer and the second MR magnetic layer are respectively laminated by contacting each other in the order; a lower shield layer and an upper shield layer that face the first MR magnetic layer and the second MR magnetic layer, respectively, and which are arranged in a matter of sandwiching the MR laminated body in an orthogonal direction relative to a film surface of the MR laminated body, and also which function as electrodes for flowing a sense current in the orthogonal direction relative to the film surface of the MR laminated body; and a bias magnetic field applying means that is established on an opposite surface from an air bearing surface (ABS) of the MR laminated body, and that applies a bias magnetic field in a direction at right angles to the ABS to the MR laminated body, wherein the lower shield layer has a first anti-parallel layer that faces the first MR magnetic layer, and that applies an anti-parallel coupling magnetic field in parallel to the ABS to the first MR magnetic field; and a first antiferromagnetic layer that is formed on the rear surface of the first anti-parallel layer viewed from the first MR magnetic layer, the first antiferromagnetic layer being in contact with the first anti-parallel layer and being exchange coupled with the first anti-parallel layer; the upper shield layer has a second anti-parallel layer that faces the second MR magnetic layer, and that applies an anti-parallel coupling magnetic field to the second MR magnetic layer, the exchange coupling magnetic field being in a parallel direction to the ABS and in an antiparallel direction to an anti-parallel coupling magnetic field applied to the first MR magnetic layer by the first anti-parallel layer; a second antiferromagnetic layer is established on the rear surface of the second anti-parallel layer viewed from the second MR magnetic field, the second antiferromagnetic layer being in contact with the second anti-parallel layer and being exchange coupled with the second anti-parallel layer; and the exchange coupling intensity relating to the exchange coupling between the second anti-parallel layer and the second antiferromagnetic layer is greater in the peripheral area of a projection area than that of the projection area of the upper shield layer side end surface of the MR laminated body to the film surface's orthogonal direction.