Ceramics-Silikáty 54, (1) 31 - 37 (2010)

Bi_1.5Zn_1.0Nb_1.5O₇ and Bi_1.5Zn_0.92Nb_1.5O_6.92 pyrochlore compositions were prepared and investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and their dielectric properties were measured. XRD of Bi_1.5Zn_0.92Nb_1.5O_6.92 gave only single phase pyrochlore but second phases were observed in the XRD of Bi_1.5Zn_1.0Nb_1.5O₇. SEM supported X-ray results but in the microstructure of Bi_1.5Zn_1.0Nb_1.5O₇ composition a Zn-rich phase was also observed in additon to pyrochlore and ZnO. Bi_1.5Zn_0.92Nb_1.5O_6.92 pyrochlore had higher dielectric constant and lower loss values than Bi_1.5ZnNb_1.5O₇ composition between 25-200°C in the frequency range of 10 kHz-2 MHz, possibly due to presence of second phases in Bi_1.5ZnNb_1.5O₇.