Patent ID: 6839206

Claim:
A magnetoresistance effect element comprising: a first pinned ferromagnetic layer configured to keep a magnetization direction thereof fixed on application of a magnetic field; a second pinned ferromagnetic layer facing the first pinned ferromagnetic layer and configured to keep a magnetization direction thereof fixed on application of the magnetic field, a surface region of the first pinned ferromagnetic layer and a surface region of the second pinned ferromagnetic layer facing each other being different from each other in composition; to provide an asymmetric voltage-resistance property has been inserted after “composition”; a free ferromagnetic layer intervening between the first and second pinned ferromagnetic layers and configured to be capable of changing a magnetization direction thereof on application of the magnetic field; a first tunnel barrier layer intervening between the first pinned ferromagnetic layer and the free ferromagnetic layer; and a second tunnel barrier layer intervening between the second pinned ferromagnetic layer and the free ferromagnetic layer.