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

X-ray-photoelectron spectroscopy (XPS) and optical measurements have b een performed to investigate the structure of electronic states in ytt rium-stabilized zirconia. From reflectivity observations, the spectral behavior of the dielectric function, of the energy loss, and of the e ffective 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 s tructure of valence and conduction states and to discuss the nature of the main optical transitions, also in connection with available theor etical data.