Patent ID: 7400137

Claim:
A magnetic sensor, comprising 4n magnetoresistive elements (where n denotes a natural number), each of the magnetoresistive elements including a ferromagnetic pinned layer and a ferromagnetic free layer stacked one on top of another with a non-magnetic intermediate layer in between, each of the magnetoresistive elements having a substantially rectangular shape, the magneto resistive elements substantially the same magnetoresistive properties, the ferromagnetic pinned layers having the same direction of magnetization, the 4n magnetoresistive elements constituting first and second element groups each formed of 2n elements, the magnetoresistive elements that constitute each of the element groups being equidistantly disposed as spaced a distance λ away from each other across the front-end and rear-end elements in a direction of a short side of the element and being series-connected in a direction of a long side of the element, the rear-end element of the first element group and the front-end element of the second element group being located as spaced a distance λ/2 away from each other in the direction of the short side of the element, the front-end element of the first element group being connected to an electric power supply while the rear-end element thereof being connected to the front-end element of the second element group, the rear-end element of the second element group being grounded, and an external magnetic field being detected through midpoint electric potential from a connection between the first element group and the second element group, wherein the magnetoresistive element satisfies the inequation, H10−50<H50−90, where H10−50 represents a magnetic field required for a resistance change from ΔR×10% to ΔR×50% with respect to a maximum amount of resistance change ΔR in process of a resistance change occurring according to the external magnetic field parallel to the direction of the short side of the element, and H50−90 represents a magnetic field required for a resistance change from ΔR×50% to ΔR×90%.