Nickel base substrate tapes for coated superconductor applications

The development and status of Ni base alloy substrate tapes for coated superconductor applications have been reviewed. Rolling assisted Biaxially Textured Substrates or RABiTSTM method comprising cold rolling and annealing of Ni gives rise to sharp cube texture ({100} Æ100æ) component which is required for subsequent epitaxial growth of the buffer and YBCO layers. However, pure Ni seems to be rather unsuitable for this purpose since its mechanical strength as well as the stability of the cube texture deteriorate at the deposition temperature of YBCO. Refractory metals, particularly, W and Mo hold the potential to be used as micro-alloying element to impart strength as well as to preserve the cube texture and maintain its stability at high temperatures. Cr and V at higher alloying level are suited for non-magnetic applications. Recent works have suggested the possibility of using substrates with multilayer architecture and this needs to be investigated further.