Patent ID: 7333303

Claim:
A magnetoresistive device, comprising: a magnetoresistive film including: a fixing layer including an iridium-manganese alloy (IrMn); a magnetization fixed layer including a first ferromagnetic layer having a magnetization direction fixed in a first direction by the fixing layer, an intermediate layer, and a second ferromagnetic layer having a magnetization direction fixed in a second direction opposite to the first direction by the fixing layer which are laminated in order from the fixing layer; a non-magnetic layer disposed on a side of the magnetization fixed layer opposite to a side where the fixing layer is disposed; and a magnetization free layer disposed on a side of the non-magnetic layer opposite to a side where the magnetization fixed layer is disposed and changing its magnetization direction according to an external magnetic field; a pair of conductive lead layers extending so as to be disposed adjacent to at least parts of both end surfaces of the magnetoresistive film and to face each other; and a current supply means for flowing a sense current in a direction where a current magnetic field toward the second direction is generated in the second ferromagnetic layer in an in-plane direction of the laminate of the magnetoresistive film through the pair of conductive lead layers, wherein the following conditional expression (1) is satisfied: 0.6 mA≦( Ms 2× T 2− Ms 1× T 1)≦1.5 mA (1) where Ms 1 is the saturation magnetization of the first ferromagnetic layer; T 1 is the thickness of the first ferromagnetic layer; Ms 2 is the saturation magnetization of the second ferromagnetic layer; and T 2 is the thickness of the second ferromagnetic layer.