X-RAY-PHOTOEMISSION SPECTROSCOPY AND OPTICAL REFLECTIVITY OF YTTRIUM-STABILIZED ZIRCONIA

X-ray-photoelectron spectroscopy (XPS) and optical measurements have been performed to investigate the structure of electronic states in yttrium-stabilized zirconia. From reflectivity observations, the spectral behavior of the dielectric function, of the energy loss, and of the effective electron number in the range 3-30 eV were obtained for single crystals with an yttria content of 12 and 24 mol%. This information, combined with binding-energy spectra from XPS, was used to infer the structure of valence and conduction states and to discuss the nature of the main optical transitions, also in connection with available theoretical data.