Patent ID: 7495869

Claim:
A magnetoresistive effect sensor comprising: a spin valve film disposed on a substrate layer, the spin valve film comprising a stacked layer structure which includes a pinned layer having a fixed magnetic orientation against an external magnetic field, a nonmagnetic spacer layer, and a free layer having a variable magnetic orientation which depends on the external magnetic field, wherein sense current flows through the pinned layer, the nonmagnetic spacer layer, and the free layer substantially in a stacked direction thereof, and wherein the pinned layer, the nonmagnetic spacer layer, and the free layer have a total thickness of at least 10 nm; insulating films disposed on both side surfaces of the spin valve film in a layer width direction, the layer width direction being parallel to an air bearing surface and perpendicular to the stacked direction; and hard magnetic films disposed on die insulating films for applying a biasing magnetic field to the free layer, wherein each hard magnetic film extends toward the free layer in a vicinity of the spin valve film, such that as each hard magnetic film extends toward the spin valve film, a cross-sectional area thereof in a plane perpendicular to the layer width direction becomes progressively smaller, wherein each hard magnetic film has, in a plane parallel to the air bearing surface, a first boundary line which at least partially faces the free layer and substantially defines an end point of the hard magnetic film in the layer width direction, wherein each hard magnetic film has: a second boundary line which feeds the substrate layer in the plane parallel to the air bearing surface; and a third boundary line which faces the side surface of the spin valve film and interconnects the first and second boundary lines, and wherein the first boundary line has an upper end which lies above an upper surface of the free layer in the stacked direction, and a bent point which lies between the first boundary line and the third boundary line, the bent point lying below a lower surface of the free layer in the stacked direction.