Growth of oxide seed layers on Ni and other technologically interesting metal substrates: issues related to formation and control of sulfur superstructures for texture optimization

The current carrying capabilities of RABiTS are connected to the crystalline quality of the seed buffer layer and the stability of the metal/seed layer interface. Our study shows that the epitaxial growth of commonly used seed layers on textured Ni is mediated by a sulfur superstructure present on the metal surface. Many structural defects generated during seed layer growth (secondary orientations, in-plane rotation, incomplete cube texture) can be related to the S surface concentration and superstructure coverage. More generally, our results indicate that the epitaxial deposition of several classes of oxides (fluorite, perovskite, RE₂O₃) on several {100}<100> fcc metals depends, in addition to chemical stability and lattice match, on the existence and optimization of S superstructures on the metal surface. On these bases, we discuss issues related to the growth of different oxides on Ni, Ni-alloys, and Pd surfaces having different chemical and structural properties.