Patent ID: 8023230

Claim:
A magnetoresistive element comprising: a first shield portion and a second shield portion; an MR stack disposed between the first and second shield portions; and a bias magnetic field applying layer disposed between the first and second shield portions and applying a bias magnetic field to the MR stack, wherein: the first shield portion includes a first single magnetic domain portion that is in a single magnetic domain state such that a magnetization thereof is directed to a first direction; the second shield portion includes a second single magnetic domain portion that is in a single magnetic domain state such that a magnetization thereof is directed to a second direction; the first and second single magnetic domain portions and the MR stack are disposed such that the MR stack is sandwiched between the first and second single magnetic domain portions; the MR stack includes: a first ferromagnetic layer magnetically coupled to the first single magnetic domain portion; a second ferromagnetic layer magnetically coupled to the second single magnetic domain portion; and a spacer layer made of a nonmagnetic material and disposed between the first and second ferromagnetic layers; and the MR stack has a front end face that receives a magnetic field to be detected, a rear end face opposite to the front end face, and two side surfaces connecting the front end face and the rear end face to each other, each of the front end face, the rear end face and the two side surfaces being located at an end in a direction intersecting a direction in which the first ferromagnetic layer, the spacer layer and the second ferromagnetic layer are stacked, the magnetoresistive element further comprising two flux guide layers each formed of a magnetic material, the two flux guide layers being disposed between the first and second single magnetic domain portions and respectively adjacent to the two side surfaces of the MR stack, wherein each of the two flux guide layers has a front end face facing toward the same direction as the front end face of the MR stack, and a rear end face opposite to the front end face; and the bias magnetic field applying layer has a front end face facing the rear end face of the MR stack and the rear end face of each of the two flux guide layers, and applies the bias magnetic field to the first and second ferromagnetic layers so that magnetizations of the first and second ferromagnetic layers change their directions compared with a state in which no bias magnetic field is applied to the first and second ferromagnetic layers.