Synthesis and dielectric relaxation studies of Ba substitution in Pb(Zn 1/3Nb 2/3)O 3 ceramics by co-precipitation method

Abstract

Coexistence of both sharp transition around ( T c1 ∼ 305 k) in lower frequency region (∼11 kHz) and broad transitions (∼350 < T c2 < 410 K) in the frequency range (11 kHz–1 MHz) of dielectric permittivity ( ɛ′) versus temperature is demonstrated in the complex perovskite barium substituted lead zinc niobate, (Pb 1− x Ba x )(Zn 1/3Nb 2/3)O 3 ( x = 0.10). To ensure homogeneous distribution of Ba 2+ ions at A-site and to avoid the microscopic segregation and clustering of Ba 2+/Pb 2+ ion in the prepared (Pb 1− x Ba x )(Zn 1/3Nb 2/3)O 3 ( x = 0.10), the material has been synthesized by substituting barium using the precursor Pb 0.90Ba 0.10CO 3 via a novel co-precipitation route. Another precursor ZnNbO 6 was prepared by columbite reaction method for preventing the formation of the unwanted pyrochlore phase. The symmetry is found to be cubic with the space group of P m 3 ¯ m at room temperature (30 °C) as is clear by X-ray diffraction and rietveld analysis. An analysis of real and imaginary part of dielectric permittivity and electric modulus with frequency at various temperatures has been performed. Using Cole–Cole model, an analysis of the imaginary part of the dielectric permittivity with frequency is performed using a distribution of relaxation times.