Interface structural evolution of YBa2Cu3Ox from a randomly oriented silver alloy substrate

In our previous work we have obtained YBCO thick films on silver alloy subs trate (SAS) via the peritectic solidification. To identify the underlying m echanism of YBCO grain growth at the substrate interface, extensive transmi ssion electron microscopy experiments were carried out in this study. A thi n "buffer" of 300 nm thickness was observed between the YBCO film and the S AS. This "buffer" was identified to be essentially the YBCO structure, howe ver lacking of the superlattice. Initially randomly oriented, these small c rystallites in the buffer gradually grow into a large grain of YBCO within the polycrystalline film. The underlying mechanism of crystal evolution on an unoriented substrate is discussed. (C) 2001 Elsevier Science B.V. All ri ghts reserved.