Electrical transport properties of ultrathin metallic films

Ultrathin metal films of Al, Au, Cr, Cu, Ru, Ta, Co90Fe10, Ni81Fe19, Ir20Mn80 with or without capping layers have been prepared using ultrahigh vacuum sputtering and their morphological and electrical properties have been studied using atomic force microscopy and four-point probe measurement, respectively. It was found that the capping layer could either enhance or reduce the conductivity, depending on the capping layer thickness and surface roughness of the underlying film. The study of magnetoresistance (MR) dependence on capping and free layer thickness is also carried out on a pseudo spin valve.