Fig. 6. Plot of ln α vs. hν for the determination of Urbach PF-4708671 (Eu) for Ba1−xSrxZr0.05Ti0.95O3 ceramics with different compositions: (a) x = 0; (b) x = 0.1; (c) x = 0.2, (d) x = 0.3, (e) x = 0.4 and (f) x = 0.5.Figure optionsDownload full-size imageDownload as PowerPoint slide
Fig. 7. Variation of band gap (Eg) and Urbach energy (Eu) for different concentrations of Ba1−xSrxZr0.05Ti0.95O3 ceramics with different compositions.Figure optionsDownload full-size imageDownload as PowerPoint slide
The microstructural details of the BSZT ceramics are shown in Fig. 8. It can be observed that the grain size is very widely distributed from submicron size to more than 1 μm with irregularly shaped grains with a change in Sr content in BZT. As the Sr content is increased, the grain size distribution is narrowed down and the grains became more spherical as can be observed from Fig. 8. The smaller grains merge with each other with the increase in Sr content and grow into larger ones, thereby increasing the fraction of the larger grains in the overall microstructure. The maximum density achieved in endergonic compounds with different Sr contents (10–50 mol%) varied from 93% to 96% of the theoretical density. All the ceramics have triple point porosity which is commonly observed in solid state oxide mixing processed ceramic materials.