Investigations on structural evolution and dielectric characteristics of high performance Bi-based dielectrics

A new system of (Bi1.5Zn1-x/3TixNb1.5-2x/3)O-7 (0 <= x <= 1.5) ceramics have been successfully developed and the dielectric properties have been systematically studied. The results showed the formation of temperature compensation dielectrics over the wide range of Ti concentrations. The incorporation of Ti4+ into the bismuth zinc niobate ceramics induce the decrease of lattice constant linear while remaining cubic pyrochlore phase. The IR spectra confirm the formation of pyrochlore structure and give information about the distribution of ions between the A and B sites. It has been found that the effect of Ti substitution on dielectric properties of sintered ceramics intensifies with a higher x. The system exhibits the novel high permittivity and low dielectric loss: the permittivity values (epsilon(r)) saturate at 160-210, and loss values remain at low values (similar to 1 x 10(-4)). The temperature dependence of permittivity is strongly dependent with the compositions. Dielectric relaxation phenomena have been observed during low temperature. New high frequency and MW materials, differed by Ti content, with temperature compensation and controllable dielectric constant of 150-210 have been developed. (C) 2005 Elsevier Ltd. All rights reserved.