Ellipsometric measurements of high-Tc compounds

Abstract
Ellipsometric measurements of the pseudodielectric function of YBa2Cu3O7−x in the energy region 1.7–9.5 eV are presented. The variations in the optical spectra as a function of oxygen concentration and for substitution of different lanthanide ions for yttrium are discussed. New results obtained with CaBi2 Sr2Cu2O8 are shown and interpreted in terms of recent band-structure calculations.