Patent ID: 7876535

Claim:
A magnetoresistive device of a CPP (current perpendicular to plane) structure, comprising a magnetoresistive unit, and a first, substantially soft magnetic shield layer positioned below and a second, substantially soft magnetic shield layer positioned above, which are located and formed such that the magnetoresistive unit is sandwiched between them from above and below, with a sense current applied in a stacking direction, characterized in that: said magnetoresistive unit comprises a non-magnetic intermediate layer, and a first ferromagnetic layer and a second ferromagnetic layer stacked and formed such that said nonmagnetic intermediate layer is sandwiched between them, at least one of said first shield layer positioned below and said second shield layer positioned above is configured in a window frame shape having a planar shape (X-Y plane) defined by the width and length directions of the device, said window framework has a front frame-constituting portion located on a medium opposite plane side in front and near where the magnetoresistive unit is positioned, and a back frame-constituting portion located in the rear of said front frame-constituting portion, the depth length of said back front-constituting portion is larger than the depth length of said front frame-constituting portion, said back frame-constituting portion partially comprises a combination of a nonmagnetic gap layer with a bias magnetic field-applying layer, said nonmagnetic gap layer is designed and located such that a magnetic flux given out of said bias magnetic field-applying layer is efficiently sent out to said front frame-constituting portion, and the combination of said nonmagnetic gap layer with said bias magnetic field-applying layer forms a closed magnetic path with a magnetic flux going all the way around said window framework, and turns the magnetization of said front frame-constituting portion into a single domain.