Infrared reflectivity of Y 1Ba 2Cu 3O 7-δ ceramics

Abstract

Good quality, reproducible surfaces have been produced on samples of Y 1Ba 2Cu 3O 7-δ (YBCO) ceramics by two different techniques. The first involves pressing against a highly polished sapphire reference surface during the densification process, and the second involves a partial extrusion procedure. The infrared reflection spectra obtained from samples prepared in these ways seem to be sufficiently reproducible to allow meaningful detailed interpretation. Significantly different IR reflection spectra have been published by the many research groups working on these materials. We suggest that our techniques have much to recommend them as standard procedures; (i) to allow more reliable intercomparison of data between different groups, and (ii) to produce spectra which would be intrinsically more valuable on samples in which the oxygen content has been systematically varied. These data have implications; (a) for suggesting an increased use of infrared reflectivity as a standard monitoring procedure in high T c superconductivity work, and (b) for the development of extrusion and other forming methods for these types of material.