Patent ID: 7715153

Claim:
A magneto-resistive effect element comprising: a free layer having a magnetization direction which varies with respect to an external magnetic field; a pinned layer which includes a stacked structure comprising an outer pinned layer which has a magnetization direction that is fixed with respect to the external magnetic field, a non-magnetic intermediate layer comprising ruthenium, and an inner pinned layer with a thickness of 3 nm or more, wherein the inner pinned layer has a magnetization direction which is fixed with respect to the external magnetic field due to anti-ferromagnetic coupling with the outer pinned layer via the non-magnetic intermediate layer; a spacer layer sandwiched between the free layer and the inner pinned layer; and an anti-ferromagnetic layer comprising an iridium manganese alloy which is in contact with a surface of the pinned layer opposite to the free layer, and which fixes the magnetization direction of the outer pinned layer with respect to the external magnetic field by exchange coupling with the outer pinned layer, wherein the outer pinned layer and the inner pinned layer comprise a cobalt iron alloy, and wherein an atomic percent of cobalt in the outer pinned layer increases from a boundary between the outer pinned layer and the anti-ferromagnetic layer toward a boundary between the outer pinned layer and the non-magnetic intermediate layer, and an atom it percent of cobalt in the inner pinned layer decreases from a boundary between the inner pinned layer and the non-magnetic intermediate layer toward a boundary between the inner pinned layer and the spacer layer.