Giant Magnetoresistance and Interface Structure in Metallic Multilayers

Abstract

The correlation between giant magnetorisitance (GMR) and interface structure were investigated in Co/Cu and Co/Cu/NiFe/Cu multilayers as well as model calculation. The calculation revealed that interfacial ferromagnetic coupling reduces MR ratio and induces triangular-like shape MR curves. ⁵⁹Co NMR measurement in zero field in a Co/Cu multilayer indicated that the temperature dependence of the interface Co hyperfine field is larger than that of the bulk Co hyperfine field, which correlates with the temperature dependence of GMR in the Co/Cu. This suggests that the GMR originates from the spin-dependent interface scattering. The correlation between interface structure and GMR was also demonstrated for Co/Cu/NiFe/Cu multilayers with non-interlayer coupling, which implies that the interface structure intrinsically affects GMR, independent of the interlayer coupling.