Influence of pyrochlore phase on the dielectric properties of the bismuth niobate system

Abstract The dielectric properties of BiNbO4 as a function of copper oxide addition level, frequency, and temperature were investigated in this work. The ceramic samples were prepared using the solid-state reaction method and different amounts of CuO were added to BiNbO4. The structural analysis was made by X-ray diffraction, and the Rietveld refinement showed the formation of the Bi1.5Nb1.5CuO7 pyrochlore phase because of the sintering of the BiNbO4 orthorhombic ceramic phase added with CuO. The morphology of the samples was studied by scanning electron microscopy and showed the distribution of grains on the fracture surface. The dielectric properties of BiNbO4, in the low-temperature range (100–370 K), were studied using the impedance spectroscopy technique in the frequency range 100 Hz to 1 MHz. The electrical results obtained, and the low sintering temperature applied, allow the applications in low-temperature co-firing ceramics (LTCC).