Dependence of Magnetoresistance and Antiferromagnetic Coupling on Preparation Conditions in Epitaxial (100)Co/Cu Superlattices

Epitaxial (100)Co/Cu superlattices were grown by dc magnetron sputtering with various Ar pressures to investigate the dependence of magnetoresistance (MR) and antiferromagnetic (AFM) coupling on preparation conditions. The MR ratio and AFM coupling were found to be larger for a sample prepared with higher Ar pressure, where X-ray and reflection high-energy electron diffractions indicate that the Co/Cu interfaces are rougher. These results are the reverse of previously reported ones in terms of the correlation between MR ratio and interface roughness. A cause of this discrepancy may be a difference in the scale of roughness.