Enhancement of microstructure, dielectric, and ferroelectric properties of Ca and Zr co-doped BaTiO3 ceramics with sintering temperatures

The objective of this study is to synthesize Ba 0.83 Ca 0.17 Zr 0.12 Ti 0.88 O 3 (BCZTO) ceramics—a novel composition near the morphotropic phase boundary (MPB) with modified Ca and Zr concentrations in BaTiO 3 —and to investigate their functional properties. The study also aims to examine in detail the effect of sintering temperature ( T S ) on the surface morphology, crystal structure, ferroelectric, and dielectric behavior. The lead-free BCZTO ceramic samples were synthesized through standard double sintering ceramic method. Structural properties was performed using XRD patterns of the ceramics, which were refined with X'Pert HighScore Plus software. X-ray diffraction and Rietveld refinement confirmed a single-phase tetragonal P4mm structure across all sintering temperatures, with a slight increase in the c/a ratio from 1.0052 to 1.0056, indicating improved tetragonality. Microstructure and elemental distribution of the ceramics were analyzed through FESEM and EDS, respectively. FESEM images show that the grain size increased significantly—from 0.42 μm at 1250 °C to 1.66 μm at 1350 °C—accompanied by a reduction in porosity with rising T S . EDS analysis confirmed the presence of all constituent elements in the ceramics under investigation. Frequency dependence dielectric constant, impedance spectra, ac conductivity, dielectric loss factor were measured using impedance spectroscopy. With the elevation of T S , the dielectric constant increases, and the ceramic sintered at 1350 °C exhibits a higher dielectric constant of 1268, accompanied by a comparatively lower dielectric loss factor of 0.067 at 100 Hz. Nyquist plots reveal that grain boundary contributions dominate the overall resistance of the synthesized ceramics. P–E hysteresis loops show that the ferroelectric properties were enhanced with rising T S and electric field strength. A maximum polarization ( P m ) of 17.17 μC/cm 2 was recorded at 1350 °C and 20 kV/cm field. The eco-friendly BCZTO ceramics, sintered at 1350 °C, displays enhanced ferroelectric and dielectric properties, which makes it suitable for applications in energy storage and microwave communication devices. • Lead-free BCZTO ceramic, a distinct chemical formula, is synthesized systematically. • Rietveld refinement reveals the formation of tetragonal structure with P4mm space group. • Both grain size ( ) and max. polarization ( P m ) values are enhanced with increasing T S . • The optimal sintering temperature for the studied ceramics is determined to be 1350°C. • The ceramic sintered at 1350°C also exhibits a higher ε ′ value with a low tanδ value.