Structural and Dielectric Properties of Ca Doped Barium Iron Niobate

Ceramic materials with high dielectric constant are being used in many electric and electro-optics applications. Ca substituted barium iron niobate with general formula (Ba1-xCax) (Fe0.5Nb0.5)O-3 with x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0 were prepared by conventional solid state reaction method. Structural properties were investigated using X-ray diffraction and scanning electron microscope. Two types of phases were observed for 0.4 <= x <= 08. Dielectric constant and loss tangent were measured using impedance analyzer in the frequency range of 20Hz-1MHz at room temperature. Dielectric constant and loss tangent were found to decrease with increasing the frequency. A relatively good combination of dielectric constant and loss tangent was obtained for x=0.2 (epsilon(r)=1441 and tan delta=0.19) at 10 KHz.