Patent ID: 7804667

Claim:
A magnetoresistive element comprising: a nonmagnetic conductive layer having a first surface and a second surface that face toward opposite directions; a pinned layer disposed adjacent to the first surface of the nonmagnetic conductive layer, a direction of magnetization in the pinned layer being fixed; and a free layer disposed adjacent to the second surface of the nonmagnetic conductive layer, a direction of magnetization in the free layer changing in response to an external magnetic field, wherein a current for detecting magnetic signals is fed in a direction intersecting a plane of each of the foregoing layers; the nonmagnetic conductive layer contains an element that is a main component of the nonmagnetic conductive layer; at least one of the pinned layer and the free layer includes a Heusler alloy layer; the Heusler alloy layer contains a Heusler alloy in which atoms of a magnetic metallic element are respectively placed at body-centered positions of unit cells, and contains an additive element that is a nonmagnetic metallic element that does not constitute the Heusler alloy, the additive element being different from the element that is the main component of the nonmagnetic conductive layer; and the at least one of the pinned layer and the free layer includes a region in which a concentration of the additive element increases as a distance from the nonmagnetic conductive layer decreases, the region being adjacent to the nonmagnetic conductive layer.