Study of Structural, Dielectric, Electrical and Optical Properties of the Sr₃CuTi₄O₁₂ Ceramics

Abstract

In the present investigation, the synthesis of the strontium copper titanate [Formula: see text] ceramic by the cost-effective solid-state reaction was reported. The structural analysis suggests a single-phase tetragonal crystal symmetry with space group P4/mmm. The average crystallite size and mechanical compressive microlattice strain are found to be 65.8[Formula: see text]nm and 0.000594, respectively. The study of the field emission scanning electron microscope (FESEM) micrograph suggests that grains and grain boundaries are uniformly distributed on the sample surface with less porosity. The study of Raman lines suggests the presence of all constituent elements, which is well supported by EDAX analysis. The UV–Vis spectroscopy analysis shows that the bandgap of SCTO is about 3.2[Formula: see text]eV suitable for photovoltaic and other higher-temperature sensor applications. The decrease of dielectric constant with frequency supports the reduction of space charge polarization. The modulus analysis suggests that the immobile charge carriers at lower and defects and oxygen vacancies at higher temperatures are responsible for the thermally activated conduction process. The calculated activation energies are 4.54[Formula: see text]meV, 4.40[Formula: see text]meV, 3.39[Formula: see text]meV and 3.29[Formula: see text]meV at 1[Formula: see text]kHz, 10[Formula: see text]kHz, 100[Formula: see text]kHz and 1[Formula: see text]MHz; the decrease with the rise of the frequency confirms a thermally activated conduction process. Thermistor constant [Formula: see text], sensitivity factor [Formula: see text] and stability factor of the sample were calculated, which confirms the characteristics of the NTC thermistor. The Nyquist and Cole–Cole semicircular arcs confirm NTCR character and are found to be suitable applications for energy storage devices and thermistors.