Patent ID: 7843668

Claim:
A magnetoresistive element comprising a first shield, a second shield, and an MR stack disposed between the first and second shields, the MR stack including a first ferromagnetic layer, a second ferromagnetic layer, and a spacer layer made of a nonmagnetic material and disposed between the first and second ferromagnetic layers, the first and second ferromagnetic layers having magnetizations that are in directions antiparallel to each other when no external magnetic field is applied to the layers, and that change directions in response to an external magnetic field, the MR stack having: a front end face that is located at an end of the MR stack taken in a direction intersecting a direction in which the first ferromagnetic layer, the spacer layer and the second ferromagnetic layer are stacked and that receives a magnetic field to be detected; and a rear end face opposite to the front end face, the magnetoresistive element further comprising: a bias magnetic field applying layer that is disposed at a location between the first and second shields and adjacent to the rear end face, and that applies a bias magnetic field to the first and second ferromagnetic layers so that the directions of the magnetizations of the first and second ferromagnetic layers become non-antiparallel to each other; an insulating layer disposed between the rear end face and the bias magnetic field applying layer and between the first shield and the bias magnetic field applying layer and touching the rear end face and the first shield; and a buffer layer made of a nonmagnetic material and disposed between the insulating layer and the bias magnetic field applying layer, wherein: the bias magnetic field applying layer includes: a hard magnetic layer; and a high saturation magnetization layer having a saturation magnetization higher than that of the hard magnetic layer; the insulating layer, the buffer layer and the high saturation magnetization layer are located between the rear end face and the hard magnetic layer; while the insulating layer and the buffer layer are located between the first shield and the hard magnetic layer, the high saturation magnetization layer is not located between the first shield and the hard magnetic layer; and the hard magnetic layer touches the buffer layer.