A strong enhancement of CPP-GMR by using large resistivity magnetic materials

We found a ferromagnetic material Co–Mn–Al that shows large specific magnetoresistance change (Δ RA) in the fully metallic current-perpendicular-to-plane (CPP) spin valve system when used for pinned and free layers. The Co–Mn–Al films were sputter-deposited at room temperature and have disorderd crystral structure. Analyzing the experimental results with the semiclassical two-current theory, we concluded that the enhancement in Δ RA is ascribed to compatibility of high resistivity and a large spin-asymmetry coefficient for the spin-dependent bulk scattering of the alloy. The results were compared with those for the conventional Co–Fe alloy and for a Co–Fe–Al alloy that also shows large Δ RA.