The influence of Bi content on dielectric properties of Bi4–xTi3O12–1.5x ceramics

Abstract

A kind of lead-free dielectric materials, such as the bismuth layered perovskite-type structure of Bi[Formula: see text]Ti3O[Formula: see text], was prepared by the conventional solid-state method at 800[Formula: see text]C and sintered at 1100[Formula: see text]C. The variation of structure and electrical properties with different Bi concentration was studied. All the Bi[Formula: see text]Ti3O[Formula: see text] samples exhibited a single structured phase. SEM could be a better approach to present the microstructure of Bi[Formula: see text]Ti3O[Formula: see text] ceramics. It could be found that the grain size of Bi[Formula: see text]Ti3O[Formula: see text] sintered at 1100[Formula: see text]C was smaller than that of others among the five samples through grain size mechanics. Through impedance spectra analysis, we knew, when the Bi content was fixed, that the dielectric constant and the loss values increased with the decrease of frequency. The Curie temperature of the five samples was about 670[Formula: see text]C. In particular, while at the frequency of 100[Formula: see text]kHz, the lowest loss was 0.001 when Bi content was 3.98. The Bi[Formula: see text]Ti3O[Formula: see text] ceramics with the minimum grain size had highest dielectric constant and the relatively low loss. Due to its high Curie temperature, high permittivity and low loss, the Bi4Ti3O[Formula: see text] (BIT) ceramics have a broad application prospect in high density memory, generator, sensor, ferroelectric tunnel junctions and so on.