Micro-Raman scattering and dielectric investigations of phase transition behavior in the BaTiO3 - BaZrO3 system

In this study, the phase transition behavior of the BaTiO3 - BaZrO3 system was studied using micro-Raman scattering and dielectric measurement techniques. BaZrxTi1-xO3 ceramics were prepared for x=0.00, 0.05, 0.08, 0.15, 0.20, and 1.00 compositions using a solid-state reaction technique. A single-phase perovskite structure of the ceramics was identified by the x-ray diffraction technique. The basic phase transition temperatures in these compositions were studied in the temperature range of 70 - 575 K. The tetragonal to cubic transition temperature was found to decrease with increasing Zr content. The orthorhombic to tetragonal transition temperature that increases with an initial increase in Zr content merges with the tetragonal - cubic transition for x≥0.15 compositions. Raman spectra of rhombohedral and orthorhombic phases could not be distinguished. Excellent agreement between the crystallographic transition temperatures obtained by both techniques suggested that Zr substituted octahedra were uniformly distributed in the material without introducing any mechanical stress. [copyright] 2001 American Institute of Physics