Patent ID: 7029771

Claim:
A magnetic sensor comprising: a free magnetic layer in which a direction of magnetization is changed in accordance with an external magnetic field applied thereto; a fixed magnetic layer in which a direction of magnetization is fixed; a nonmagnetic material layer provided between the free magnetic layer and the fixed magnetic layer; and antiferromagnetic layers fixing the magnetization of the fixed magnetic layer by exchange coupling, wherein lengths in a first direction of the free magnetic layer, the nonmagnetic material layer, and the fixed magnetic layer are formed larger than respective widths thereof in a second direction orthogonal to the first direction, the direction of magnetization of the free magnetic layer is preferentially oriented in the first direction by shape anisotropy, the fixed magnetic layer has a multilayer structure composed of a second magnetic layer in contact with the nonmagnetic material layer, an interlayer, and a first magnetic layer provided in that order, the antiferromagnetic layers are provided with an intermediate region having a predetermined length provided therebetween in the first direction so as to be in contact with the first magnetic layer, a direction of magnetization of the first magnetic layer is fixed by the exchange coupling in a direction crossing the first direction, a direction of magnetization of the second magnetic layer is fixed antiparallel to that of the first magnetic layer, electrical resistance is changed by the direction of magnetization of the free magnetic layer and that of the fixed magnetic layer at the intermediate region, a nonmagnetic metal layer is disposed at the intermediate region, the nonmagnetic metal layer having the same composition as that of the antiferromacinetic layers, being in contact with the first magnetic layer, having a small thickness as compared to that of the antiferromagnetic layers to form an irregular crystal structure, a crystal of the nonmagnetic metal layer and a crystal of the fixed magnetic layer at the intermediate region are placed in an epitaxial or a heteroepitaxial state, and the fixed magnetic layer has an open end surface at a face opposing a recording medium, and the entire nonmagnetic metal layer or a part thereof in the vicinity of an interface with the first magnetic layer of the fixed magnetic layer has a face-centered cubic (fcc) structure, and equivalent crystal planes represented by a {111} plane are preferentially oriented in a direction parallel to the interface.