Dielectric properties of bismuth ferrite-bismuth titanate ceramic composite

Abstract

In this paper the BiFeO3//Bi4Ti3O12 (BF//BiT) ceramic-ceramic composites with 0-3 connectivity were prepared from BiFeO3 and Bi4Ti3O12 ceramic powders by free sintering method at T=900 C, for different concentration of the BF ceramic phases. Bi4Ti3O12 and BiFeO3 ceramic powders were synthesized by the conventional mixed oxide method (MOM). Synthesized BF powder was dispersed in a BiT solution and next such composite was pressing and sintering. Crystalline structure was studied by X-ray diffraction method. The dielectric properties of the BF//BiT ceramic composites were also investigated. Temperature dependence of dielectric permittivity of BF//BiT composites was measured in the frequency range of f =10kHz-100kHz. It was found, that properties of the ceramic-ceramic composite are not a simple sum of properties of the phases constituting the composite but they depend on both the way of connectivity and mutual influence of the phases on each other. The abrupt increase in permittivity may indicate an excess of the percolation threshold, so the ceramic composite for the concentrations of the BF ceramic phase cV >10% cannot be indexed as composites with 0-3 connectivity.