  The epitaxial deposition of the first oxide buffer layer (seed layer) on
biaxially textured Ni tape for coated conductors is a critical step that is
dependent on the atomistic surface condition of the metal. We present a study
of the {100}<100> biaxially textured Ni (001) surface and seed-layer growth
using in situ reflection high-energy electron diffraction (RHEED) and Auger
electron spectroscopy (AES). Our observations are consistent with formation of
a c(2 x 2) 2-D superstructure due to surface segregation of sulfur contained in
the metal. We show that this superstructure can have a dramatic effect on the
heteroepitaxial growth of oxide seed layers. In particular, the surface
superstructure promotes the (200) epitaxial oxide growth of Y2O3-stabilized
ZrO2 (YSZ), which is necessary for the development of high-Jc superconducting
films for coated conductors.
