Abstract:
A new family of pyrochlore-type oxides in the Ca-Y-Ti-Nb-O system has been prepared by the conventional solid-state route. These compounds have a dielectric constant (K) in the range 27-92 and, further, the dielectric properties are found to be independent of frequency in the 100 Hz to 1 MHz range for all the compositions in the temperature range 30 degrees-100 degrees C. Their temperature coefficient of the dielectric constant is negative and in the range -80 to -612 ppm/degrees C. Rietveld analysis of the X-ray diffraction data establishes a cubic pyrochlore-type phase in the space group Fd3m (no. 227). A variation in the stoichiometry of the cations in the system does not change the pyrochlore-type structure.
