Impedance spectroscopy study in lead-free (0.75) Ba0.95Ca0.05Ti0.95Sn0.05O3/(0.25) Ni0.7Zn0.3Fe2O4 particulate composite

Abstract

Bi-phasic lead-free particulate composite of 75 wt.% Ba_0.95Ca_0.05Ti_0.95Sn_0.05O₃—25 wt.% Ni_0.7Zn_0.3Fe₂O₄ (BTCS/NZFO) was synthesized by solid-state reaction method. The crystallographic phase formation of the composite was confirmed by the Rietveld refinement analysis of the X-ray diffraction data. Dielectric and impedance data of the composite sample were analyzed over a wide range of frequency and temperature domains. Maxwell–Wagner-type relaxation and thermally activated charge hopping were observed in the composite samples in frequency and temperature-dependent dielectric spectra. The impedance spectroscopy measurements revealed a non-Debye-like dielectric relaxation prevailing in the composite. It also confirmed the contribution of grain and grain boundary effect in the electrical properties of the composite with the absence of surface charge polarization. The frequency dependent conductivity behavior obeys Jonscher’s power law and confirms the presence of correlated barrier hopping (CBH) conduction in the composite. High dielectric constant (ε_r) with low loss (tan δ) makes this composite a promising candidate for capacitor and high-frequency device application.