Pyrochlore-based oxides with small temperature coefficient of dielectric constant

Abstract

Pyrochlore based oxides with small temperature coefficient of dielectric constant (TCK) in Ca–RE–Ti–M–O (RE=Sm or Dy and M=Nb or Ta) system are reported. The 1MHz dielectric constants of these oxides vary from 26 to 102. The TCK in the vicinity of room temperature (20°C) dramatically decreases, from more than −200 for CaRETiMO7 to less than −3ppm∕°C in the solid solutions of CaRETiNbO7–CaRETiTaO7 phases. Rietveld analysis of the x-ray diffraction data establishes a cubic pyrochlore-type phase in the space group Fd3m (No. 227).