In this report we present a method improving GMR characteristics by replacing the ferromagnetic materials of the metal-based spin-valves in current-perpendicular-to-plane (CPP) geometry. AΔR (the product of the element area, A, and the change in resistance, ΔR) was investigated for three kinds of ferromagnetic materials: Co₉₀Fe₁₀ (material A), Fe₅₀Co₅₀ (material B), and Fe₅₀Co₅₀ with 0.13 nm Cu layers (material C). AΔR is 1.0 mΩμ², 1.6 mΩμm², and 2.9 mΩμm² for materials A, B, and C, respectively. A dual-type spin valve using material C exhibited an AΔR value of 5.2 mΩμm². Simple analysis using the Valet-Fert model leads to two results. The first is that both the spin-dependent interface and bulk resistance are enhanced when material A is replaced by material B. The second is that the spin-dependent bulk resistance is increased when material B is replaced by material C. These results suggest the possibility of increasing AΔR without increasing the element resistance AR of spin valves in CPP geometry.

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