Mixture behavior and microwave dielectric properties of (1-x)Ca2P2O7-xTiO(2)

Abstract

(1-x)beta-Ca2P2O7-xTiO(2) were prepared by solid-state reaction. The mixture behavior and microwave dielectric properties were investigated using X-ray powder diffraction and a network analyzer, respectively. X-ray powder diffraction patterns showed that beta-Ca2P2O7 and TiO2 existed in a mixture form, which was also confirmed by SEM analysis. It was shown that TiO2, which has positive temperature coefficient of the resonant frequency (tau(f)), compensated the negative tau(f) of beta-Ca2P2O7 (-53 ppm/degrees C) through mixture formation. The variation of dielectric properties with a function of TiO2 contents could be explained using mixture rule. In the 0.3 < x < 0.4 regions, tau(f) value could be successfully reduced almost zero. In particular, at x=0.3, good microwave dielectric properties was obtained: Q x f = 44,000, epsilon(r) = 10.9, and tau(f) = -11 ppm/degrees C. (c) 2005 Elsevier Ltd. All rights reserved.