Structural, Optical, and Ferroelectric Properties of Ba-Substituted CaTiO 3 Ceramics

Calcium Barium Titanate ceramics were synthesized and investigated to assess the effect of Ba 2+ substitution on the structural, vibrational, optical, and ferroelectric properties. A single-phase perovskite structure with a gradual peak shift toward lower 2 θ values is confirmed by X-ray diffraction. An increase in crystallite size from 165 to 244 nm with decreasing dislocation density and variable microstrain was revealed by Williamson-Hall and Debye–Scherrer analyses. FTIR and Raman spectroscopy showed characteristic Ti-O vibrational modes, with band shifts reflecting local lattice distortion and enhanced symmetry. Optical absorption and Tauc plots indicated a systematic band gap reduction from 3.50 eV to 3.10 eV, accompanied by an increase in Urbach energy (0.32–0.49 eV), confirming the role of defect states in band tailing. Optical conductivity spectra exhibited enhanced electronic transitions in the UV region. Ferroelectric P-E hysteresis measurements demonstrated a transformation from incipient ferroelectricity in CaTiO 3 to well defined loops in Ba-substituted samples, with optimum remanent polarization (116.912 μC cm −2 ) and highest coercive field (−79.385 V cm −1 ). These results establish Ba substitution as an effective strategy to tailor the structural perfection, dielectric response, and optical band structure of CaTiO 3 ceramics, making CBT compositions promising for multifunctional optoelectronic and ferroelectric device application.