Structural, dielectric, and impedance study of ZnO-doped barium zirconium titanate (BZT) ceramics

Polycrystalline lead-free BaZr0.15Ti0.85O3 ceramics doped with ZnO (0 aecurrency sign x aecurrency sign 2 wt%) were produced via mixed oxide solid-state reaction method. X-ray diffraction confirmed the presence of a single phase having tetragonal symmetry and having space group P4 mm. Scanning electron microscopy confirmed an increase in the density of microstructure and enlargement of grains with increase in ZnO concentration. Complex impedance spectroscopy revealed non-Debye type relaxation phenomenon. It was observed that an increase in the resistance of grain boundaries and decrease in that of grain interior (bulk) occurred with an increase in temperature. Relaxation time decreased with increase in temperature for both grain boundaries and grain interior. Understandings obtained from this work might be helpful in engineering the microstructure of BZT-based ceramics for useful applications.