Thin-film magnetic head comprising bias layers having a large length in track width direction

Abstract

The thin-film magnetic head of the present invention comprises an MR sensor wherein a first ferromagnetic layer in which a magnetization direction is fixed with respect to external magnetic fields, a non-magnetic intermediate layer, and a second ferromagnetic layer in which a magnetization direction changes with respect to the external magnetic fields are stacked, and wherein a sense current flows substantially parallel to the stacked layer surface. The thin-film magnetic head comprises a pair of bias layers for exerting a bias magnetic field upon the MR sensor; the bias layers extending substantially symmetrically from two sides of the MR sensor in a direction of track width of a recording medium, each bias layer being connected with the MR sensor over a length which is substantially the same as the MR sensor in a direction perpendicular to the air bearing surface; and each bias layer having a shape which is contained within an imaginary rectangle which has its long sides along the air bearing surface in the direction of the track width of the recording medium and its short sides in the direction perpendicular to the air bearing surface and which contacts the short side of the imaginary rectangle which is opposite the short side which contacts the MR sensor. The thin-film magnetic head further comprises a pair of lead layers for supplying the sense current to the MR sensor each extending from the air bearing surface to cover at least a portion of each of the bias layers.