Influence of Dopants on Structure of Polycrystalline Bismuth Niobate

Bismuth niobate (BiNbO₄) has attracted attention as a low-fired ceramics with promising microwave application potential. BiNbO₄ ceramics was fabricated by mixed oxide method and sintered at temperature T<1000°C. As the sintering aids a small amount of CuO oxide was used. The crystalline structure of the ceramic samples was examined by X-ray diffraction method at room temperature. The Rietveld refinement method was used for analysis of diffraction data. As a result an influence of dopants on crystal structure of bismuth niobate (BiNbO₄) ceramics was revealed. It was found that fabricated BiNbO₄ ceramics adopted the orthorhombic symmetry (α-BiNbO₄ phase, Pnna (52) space group). Small differences in elementary cell parameters were found.