Abstract

Characteristics of different Pr₆O₁₁ ceramic composites were studied using photopyroelectric spectroscopy. The amount of Pr₆O₁₁ in the composite was varied from 0.1 to 0.75 mol% at the sintering temperature of 1190 and 1270°C. It was found that optical energy band-gap (E_g) of the composite is reduced by increasing the amount of Pr₆O₁₁ in the composite at both sintering temperatures. However, the decrease in E_g was relatively less at a sintering temperature of 1270°C as compared to that of 1190°C. XRD analysis showed that all samples have two phases, that is ZnO and intergranular layers composed of Pr₆O₁₁ and few small peaks of Pr₂O₃. EDAX results further showed that the Pr₆O₁₁and Pr₂O₃ were segregated in the grain boundaries. Maximum grain size of 5.85 µm and relative density of 94.5% were found in these ceramics at x = 0.1 and 0.5 mol%, respectively, for 1270°C sintering temperature.

Key words: Photopyroelectric spectroscopy, optical energy band gap, Pr₆O₁₁, ZnO.