Patent ID: 8852957

Claim:
A magnetic sensor comprising: a magnetoresistive effect film; a current source for supplying a spin-polarized current to the magnetoresistive effect film; and a detector for detecting whether a magnetic material is present or not, or for detecting a number of magnetic particles, wherein the magnetoresistive effect film comprises: a detection layer comprising a magnetic film, the magnetization direction of which is changed by perpendicularly supplying the spin-polarized current from the current source to the magnetoresistive effect film; a magnetized pinned layer comprising a magnetic film, the magnetization direction of which is not changed by the perpendicularly supplying of the spin-polarized current from the current source to the magnetoresistive effect film; and a non-magnetic film, which is formed between the detection layer and the magnetized pinned layer, wherein the detection layer is thinner than the magnetized pinned layer, the thickness of said detection layer is smaller than a spin diffusion length, and the thickness of said pinned layer is larger than the spin diffusion length, and wherein an electron of the spin-polarized current is supplied from a side of the detection layer.