Spin-valve magnetoresistance sensor and thin-film magnetic head

A spin-valve magnetoresistance sensor comprising:

• a free-side ferromagnetic structure;
• a fixed-side ferromagnetic structure;
• a nonmagnetic spacer layer that separates the free-side and fixed-side ferromagnetic structures;
• an antiferromagnetic layer disposed adjacent the fixed-side ferromagnetic structure to pin the fixed-side ferromagnetic structure;
• and
• a back layer nonmagnetic metal structure consisting of two or more nonmagnetic metal layers disposed directly on the free-side ferromagnetic structure;
• and
• a protective layer that covers the back layer.

A thin-film magnetic head comprising:

• a substrate;
• an insulating layer on the substrate;
• a spin-valve magnetoresistance sensor disposed on the insulating layer, the spin-valve magnetoresistance sensor including:
• a free-side ferromagnetic structure;
• a fixed-side ferromagnetic structure;
• a nonmagnetic spacer layer that separates the free-side and fixed-side ferromagnetic structures;
• an antiferromagnetic layer disposed adjacent the fixed-side ferromagnetic structure to pin the fixed-side ferromagnetic structure;
• and
• a back layer structure consisting of two or more nonmagnetic metal layers disposed directly on the free-side ferromagnetic structure.