Large magnetic moment enhancement and extraordinary Hall effect in Co/Pt superlattices

High quality (111) and (100) oriented Co/Pt superlattices have been prepared using the magnetron sputtering technique. The extraordinary Hall effect and magnetic properties in a series of these Co/Pt superlattices have been studied. We have established the existence of a large enhanced moment at the Co/Pt interfaces. Tensile strain in the magnetic layers is found to dominate the perpendicular magnetic anisotropy for the (111) orientation. From a systematic variation of the Co layer thickness we have determined that the extraordinary Hall resistivity is dominated by interface scattering. Further, large deviations from the commonly used scaling relations linking the extraordinary Hall resistivity and the ordinary resistivity are observed. These are discussed within a model proposed by Zhang.