Study of the local structures and their thermal evolution in a HfO2-20 mol% CaO lm

TAYLOR, M.A., RIVAS, P.C., DE SANCTIS, O., PASQUEVICH, A.F., MARTINEZ, J.A., AND CARACOCHE, M.C

Buenos Aires

Conferencia; At the Frontiers in Condensed Matter; 2006

A film of HfO2-20 mol % CaO prepared by sol-gel has been grown onto Al2O3 by dip coating. The film is investigated by using Differential Thermal Analyses (DTA-TGA), X-ray diffraction (XRD) as a function of annealing temperatures and the Perturbed Angular Correlation (PAC) technique in temperature and after annealing. XRD and DTA experiments were performed in air and PAC measurements in air and vacuum. XRD on the as-prepared material shows a cubic structure and in agreement PAC results exhibit mainly a cubic hyperfine interaction. After annealing at 850oC the monoclinic phase appears and turns to be predominant upon cooling from 1000oC. PAC results, in progress, will be compared with the XRD and DTA thermal evolution. A comparison with results obtained in other calcia stabilized hafnia ceramics will also be carried out.