Study of the structural, morphological, and J–V characteristics of Zr-doped barium calcium strontium titanate

Abstract

Barium calcium strontium titanate (BCST) ceramics are promising materials for energy storage and dielectric applications, but their performance is often limited by high leakage currents and structural instability. To address these, Zr-doped BCST (Ba_0.7Ca_0.15Sr_0.15Zr_xTi_(1-x)O₃; x = 0.0, 0.1, 0.15, 0.2) ceramics were synthesized via the solid-state reaction method with the objective of reducing leakage currents in BCST ceramics. X-ray diffraction (XRD) analysis confirmed a single-phase-pseudocubic ABO3 structure with space group Pm-3mn all samples and a secondary ZrO2 phase in Zr-doped samples. Rietveld refinement revealed an increase in lattice parameters and unit cell volumes with higher doping, ranging from 62.483 to 63.363 ų. The SEM images showed cubic and rod-shaped morphologies with agglomerates and pores, with grain sizes ranging between 0.543 μm and 0.727 μm. EDS analysis confirmed the presence of all constituent elements. Current density–voltage (J–V) analysis showed that the leakage current density increased non-linearly with voltage for all samples, with Zr doping significantly reducing leakage currents by enhancing chemical stability and suppressing electron jumps between Ti⁴⁺ and Ti³⁺. Among the samples, undoped BCST exhibited the highest leakage current, while Zr-doped samples showed improved resistivity and lower leakage currents. These properties make Zr-doped BCST ceramics promising candidates for energy storage devices and dielectric applications requiring high resistivity and low leakage currents.