Crucible corrosion in the melt processing of YBa2Cu3O7-δ superconductors

Full text: YBa2Cu3O7- (YBCO) single crystals are currently grown by thermal crystallisation from a flux of Ba2Cu3O2-CuO at approximately 1000 deg C using the so-called self flux method. Under these conditions, commonly available crucible materials are corroded by the highly reactive melt. Crucible corrosion can cause chemical contamination of single crystals, masking the intrinsic physical and magnetisation properties by which researchers are attempting to understand the origin of high-temperature superconductivity. Contamination or changing composition of the flux causes many problems including limited crystal size, poor experimental control and poor reproducibility. The use of inert crucibles is required for the growth of high quality single crystals, for the application of advanced crystal growth techniques and the production of films without substrate contamination