Patent ID: 7738220

Claim:
A magnetoresistance effect element, comprising: a nonmagnetic spacer layer; first and second ferromagnetic layers separated by the nonmagnetic spacer layer, the first ferromagnetic layer having a magnetization direction at an angle relative to a magnetization direction of the second ferromagnetic layer at zero applied magnetic field, the magnetization of the first ferromagnetic layer freely rotating in a magnetic field signal; a magnetoresistance effect-improving layer comprising a metal-alloy film and disposed in contact with the first ferromagnetic layer so that the first ferromagnetic layer is disposed between the nonmagnetic spacer layer and the magnetoresistance effect-improving layer, the metal-alloy film disposed in contact with the first ferromagnetic layer, the metal-alloy film comprising first and second elements; and a nonmagnetic underlayer or a nonmagnetic protecting layer disposed in contact with the magnetoresistance effect-improving layer so that the magnetoresistance effect-improving layer is disposed between the first ferromagnetic layer and the nonmagnetic underlayer or the nonmagnetic protection layer, wherein the metal element of the first ferromagnetic layer is nickel, said first ferromagnetic layer being a Ni-alloy, wherein said first element of the said metal alloy film is Ru and said metal alloy film has Ru as a main component.