Giant magnetoresistance in heterogeneous Cu–Co and Ag–Co alloy films (invited)

Giant magnetoresistance in sputtered single films of Cu–Co and Ag–Co heterogeneous alloys is discussed. The films consist of Co-rich precipitates in a nonferromagnetic matrix. The Ag–Co films have higher Δρ/ρ and Δρ values than the Cu–Co films, possibly due to less Co dissolved in the Ag matrix. Δρ scales inversely with precipitate particle size, implying that Co-rich clusters ≤20 Å diameter may be most effective for spin dependent scattering. This trend of the data and a phenomenological model suggest that interfacial spin dependent scattering is significantly stronger than the scattering within the Co-rich particles.