Formula omitted] and [formula omitted] textured Ag tapes for biaxially oriented YBa 2Cu 3O 7 coated conductors

Abstract

Textured Ag tape is one of the most ideal substrates for the next generation high- T c wires operable in liquid nitrogen, because Ag is the only metal on which we can grow high- T c superconducting films without any chemical reactions. The {1 1 0} plane was reported to be the most suitable one for obtaining the biaxially aligned YBa 2Cu 3O 7 films among the various crystal planes of Ag. We obtained {1 1 0}〈1 1 2〉 and {1 1 0}〈1 1 0〉 textured Ag tapes by cold rolling and subsequent heat treatments. The texture of the tape after cold rolling was typical “brass type”, and the 800 °C annealing in Ar gave {1 1 0}〈1 1 2〉 texture, while {1 1 0}〈1 1 0〉 texture was obtained by the 800 °C annealing in dry air. Careful control of the cold rolling and the heat treatment conditions gave the very smooth surfaces and the shallow grooves at grain boundaries.