Investigation of orthorhombic–tetragonal structural crossover in (Ba_0.92Ca_0.08)(Zr_0.05Ti_0.95)O₃

Abstract

The orthorhombic to tetragonal phase transition in (Ba 0.92 Ca 0.08 )(Zr 0.05 Ti 0.95 )O 3 was investigated using high-temperature X-ray diffraction between 260 and 333 K. The results established the presence of tetragonal ( P 4 mm ) and orthorhombic ( Amm 2) phase co-existence in the temperature range of 293 ≤ T ≤ 313 K. The tetragonal phase was found to increase from 27% at 293 K to 76% at 313 K. The structural refinement and line-profile analysis ruled out the presence of an intermediate monoclinic structure during P 4 mm → Amm 2 crossover. The analysis shows a pure orthorhombic ( Amm 2) structure for T < 293 K and tetragonal for T > 313 K.