Dielectric properties and microstructure of Ca5Nb2TiO12 and Ca5Ta2TiO12

The 1 MHz dielectric properties of Ca5Nb2TiO12 and Ca5Ta2TiO12 compounds were reported recently. Both compounds have a common characteristic dependence of the temperature coefficient of dielectric constant (TCK) and dielectric constant (epsilon (r)) on sintering temperature. For both compounds a TCK m to distorted Pnma (with the a(-)b(+)a(-) tilt of octahedra) structures at temperatures that coincide with the observed kinks at T-A1 and T-A2 in the TCK(T-s) and K(T-s) curves. (C) 2001 Published by Elsevier Science Ltd. All rights reserved.