Comprehensive analysis of structural, optical, dielectric and electrical properties of novel compound (K0.5Bi0.5)CaTi2O6 for multifaceted applications

A complex perovskite oxide (K0.5Bi0.5)CaTi2O6 was synthesized using the solid-state diffusion method at optimized high temperature. Structural characterization using X-ray diffraction (XRD) and Raman spectroscopy at room temperature confirmed phase formation with tetragonal crystal structure belonging to P4mm space group symmetry. From Rietveld refinement of XRD data the cell parameters were obtained as a = b = 3.8763 & Aring; and c = 3.8858 & Aring;. Scanning electron microscopy (SEM) was employed to examine the material's surface morphology, revealing well-defined cuboid shaped grains, while energy-dispersive X-ray Spectroscopy (EDX) analysis confirmed the presence of all constituent elements with desired weight percentage. Optical properties, investigated via UV-Visible spectroscopy revealed a direct band gap value of 3.14 eV suggesting material's potential use for photocatalytic and optoelectronic applications. Dielectric studies presented material's ferroelectric nature which was validated through P-E loop study. A temperature stable dielectric response in the high-frequency region highlights its suitability for high-frequency electronic applications. Study of electrical microstructure and transport properties via impedance and modulus formalism suggested a non-ideal electrical response, accompanied by negative temperature coefficient of resistance (NTCR) behaviour. Estimation of thermistor parameters from strong dependence of bulk dc conductivity indicated the possible application of this prepared material as NTC thermistor. Frequency dependent ac conductivity data at different temperatures followed Jonscher's power law. Temperature-dependent ac conductivity study at some frequencies indicated Arrhenius type thermally activated electrical process occurring in the material. The activation energies estimated from different approaches suggested involvement of same type of charge carriers in different relaxation and conduction processes.