Journal of the American Ceramic Society, Vol.90, No.8, 2409-2414, 2007
Characteristics of high-Q microwave dielectric ceramics Nd(Co1/2Ti1/2)O-3 with CuO addition
We report the microwave dielectric properties and the microstructures of Nd(Co1/2Ti1/2)O-3 ceramics prepared by the conventional solid-state route. The prepared Nd(Co1/2Ti1/2)O-3 exhibits a mixture of Co and Ti showing a 1:1 order in the B site. Lowering the sintering temperature (as low as 1260 degrees C) and promoting the densification of Nd(Co1/2Ti1/2)O-3 ceramics could be effectively achieved by adding CuO (up to 0.75 wt%). At 1350 degrees C, Nd(Co1/2Ti1/2)O-3 ceramics with 0.5 wt% CuO addition possess a dielectric constant (epsilon(r)) of 27.6, a Q x f value of 165000 GHz (at 9 GHz), and a temperature coefficient of resonant frequency (tau(f)) of -20 ppm/degrees C. By comparing with pure Nd(Co1/2Ti1/2)O-3 ceramics, incorporating additional CuO helps to render a dielectric material with a higher dielectric constant, a smaller tau(f) value, and a 20% dielectric loss reduction, which makes it a very promising candidate for applications requiring low microwave dielectric loss.