New Family of Dielectric Materials in Ca–Y–Ti–Nb–O System Having Pyrochlore Type Structure
Authors: Nair, K. Ravindran; Rao, P. Prabhakar; Raj, Anupama V.; Joseph, Smila K.; Chandran, Marottikunnathu Raman; Koshy, Peter
Source: Journal of the American Ceramic Society, Volume 90, Number 11, November 2007 , pp. 3656-3659(4)
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°–100°C. Their temperature coefficient of the dielectric constant is negative and in the range −80 to −612 ppm/°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.
Document Type: Research Article
Affiliations: Materials and Minerals Division, Regional Research Laboratory, Trivandrum 695 019, India
Publication date: November 2007