Patent ID: 7715154

Claim:
An apparatus, comprising: a ferromagnetic free layer having a first magnetic moment and having a magnetization that rotates in response to an external magnetic field; a first ferromagnetic reference layer positioned adjacent to a first side of the ferromagnetic free layer and having a second magnetic moment that is greater than the first magnetic moment of the free layer; a second ferromagnetic reference layer positioned adjacent to a second side of the magnetic free layer and having a third magnetic moment that is greater than the first magnetic moment of the free layer; a first non-magnetic spacer layer positioned between the ferromagnetic free layer and the first ferromagnetic reference layer; a second non-magnetic spacer layer positioned between the ferromagnetic free layer and the second ferromagnetic reference layer; and a source of magnetic field for biasing the first and second ferromagnetic reference layers, wherein the magnetizations of the first and second reference layers are aligned parallel to each other and along the same direction.