Dielectric, Electric, and Pyroelectric Properties of Ba_1-xCa_xTiO₃ Ceramics

In this study, we investigate the dielectric, electric, and pyroelectric properties of Ba_1-xCa_xTiO₃ (BCT) ceramics with compositions of x = 0.2, 0.25, and 0.3. The ceramics were synthesized using the solid-state reaction method. A microstructural analysis was performed using scanning electron microscopy (SEM), revealing that calcium concentration influences grain size and morphology, with BCT20 showing larger, hexagonal grains, while BCT25 and BCT30 exhibited smaller, irregular grains. Phase composition and crystalline structure were characterized via X-ray diffraction (XRD), which confirmed the absence of secondary phases and a predominantly tetragonal P4mm structure for BCT20 and BCT25. However, BCT30 showed an additional orthorhombic (Pbam) phase at 5.9 wt. % alongside the dominant tetragonal phase. Dielectric measurements revealed that increasing the calcium concentration shifts the temperature of dielectric permittivity maximum to lower values, correlating with a shift in the ferroelectric-paraelectric phase transition. Pyroelectric measurements indicated the highest pyroelectric current for BCT25, while BCT30 showed the maximum thermally stimulated depolarization current.