Magnetoresistive device, thin film magnetic head, head gimbal assembly, head arm assembly, magnetic disk apparatus, synthetic antiferromagnetic magnetization pinned layer, magnetic memory cell, and current sensor

A magnetoresistive device comprising:

• a magnetization free layer whose magnetization direction changes according to an external magnetic field;
• a nonmagnetic spacer layer which is in contact with one of faces of the magnetization free layer;
• a synthetic antiferromagnetic pinned layer provided on the side opposite to the magnetization free layer, of the nonmagnetic spacer layer, the synthetic antiferromagnetic pinned layer including, in order from the side of the magnetization free layer, a first magnetization pinned layer whose magnetization direction is pinned in a predetermined direction, a nonmagnetic intermediate layer made of a ruthenium copper alloy (RuCu), and a second magnetization pinned layer whose magnetization direction is pinned opposite to the magnetization direction of the first magnetization pinned layer;
• and
• a pair of electrode layers provided on both sides, in a stacking direction orthogonal to a stack surface, of a lamination which is configured of the synthetic antiferromagnetic pinned layer, the nonmagnetic spacer layer and the magnetization free layer, the pair of electrode layers providing the lamination with read current in the stacking direction,
• wherein the first magnetization pinned layer includes a first adjacent layer having a magnetic thickness of 367 kA to 1,312 kA and forming an interface with the nonniagnetic intermediate layer,
• the second magnetization pinned layer includes a second adjacent layer having a magnetic thickness of 230 kA to 1,175 kA and forming an interface with the nonmagnetic intermediate layer, and the nonmagnetic intermediate layer is made of a ruthenium copper alloy containing ruthenium (Ru) in a range from 34 atom percent (at %) to 85 atom percent (at %), and has a thickness of 0.6 nm to 1.0 nm.