Influence of spacer layer thickness on the current-in-plane magnetoresistance in Co/Cu multilayered films

This study investigates the magnetoresistance (MR) properties of Co/Cu/Co sandwich structures with a Co layer thickness of 20 Å, focusing on the influence of the Cu layer thickness on MR under varying interface and surface qualities. Theoretical modeling, based on the semiclassical Boltzmann approach, predicts that the MR ratio is significantly influenced by Cu layer thickness due to spin-dependent scattering of conduction electrons at the Co/Cu interfaces. Numerical results indicate that MR increases with Cu layer thickness ranging from 5 Å to 60 Å, reaching an optimal point, after which it declines, provided the interface roughness is zero. High-quality, smooth interfaces and surfaces are found to enhance MR ratios by reducing spin-independent scattering and reinforcing the spin-dependent MR effect. The excellent overall agreement between theoretical and experimental findings underscores the crucial role of Cu layer thickness and interface and surface quality in enhancing MR in Co/Cu multilayers. These results have practical implications for potential applications in data storage and sensor technologies, where optimizing MR properties is essential.