Patent ID: 8669628

Claim:
A magnetoresistive element comprising: a first magnetic layer having an axis of easy magnetization perpendicular to a film plane, and an invariable magnetization direction; a second magnetic layer having an axis of easy magnetization perpendicular to a film plane, and a variable magnetization direction; a first nonmagnetic layer provided between the first magnetic layer and the second magnetic layer; a third magnetic layer formed on a surface of the first magnetic layer, which is opposite to a surface on which the first nonmagnetic layer is formed, the third magnetic layer comprising a magnetization direction antiparallel to the magnetization direction of the first magnetic layer: a fourth magnetic layer formed on a surface of the second magnetic layer, which is opposite to a surface on which the first nonmagnetic layer is formed, the fourth magnetic layer comprising a magnetization direction antiparallel to the magnetization direction of the first magnetic layer: a second nonmagnetic layer located between the first magnetic layer and the third magnetic layer; and a third nonmagnetic layer located between the second magnetic layer and the fourth magnetic layer, wherein the thickness of the fourth magnetic layer is smaller than the thickness of the third magnetic layer, and the third magnetic layer and the fourth magnetic layer are made of the same material.