Bi As An Antisurfactant In Heteroepitaxial Growth Of Co/Au(111) Multilayers

The influence of additional surface species of Bi atoms on the structural and magnetic properties of Co/Au (111) multilayers deposited using molecular beam epitaxy has been studied by reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD), grazing incidence X-ray reflectivity (XRR) and a vibrating sample magnetometer (VSM). The initial deposition of a Bi submonolayer onto the Au (111) buffer layer prior to the deposition of a Co/Au multilayer changed the heteroepitaxial growth of the Co/Au multilayer. The RHEED results proved that Bi reduced the layer-by-layer growth of the Co/Au multilayer. The results of XRD and XRR revealed that interfaces of the Co/Au multilayers with the predeposited Bi layer were rougher than those without Bi. These results indicated that Bi worked as an antisurfactant to enhance the three-dimensional island growth of the Co/Au multilayer. The coercive force and remnant magnetization of the Co/Au multilayers was enhanced by the predeposition of Bi. However, when the Co layer thickness was greater than 15 angstrom, the magnetic anisotropy energy of the Co/Au multilayers decreased due to the deposition of the Bi layer.