Crystal structure and microwave dielectric properties of ZnTi(Nb1-xTax)(2)O-8 ceramics

Abstract

The crystal structure and microwave dielectric properties of ZnTi(Nb1-xTax)(2)O-8 (0 <= x <= 1) ceramics sintered at 1200 degrees C for 2 h were investigated. For x<0.5, solid solution phases with the alpha-PbO2 structure, typical of ZnTiNb2O8, were obtained, whereas for 0.5 <= x<1, mixtures of two solid solutions each respectively based on the alpha-PbO2 structure and a trirutile structure, were obtained. The relative amount of the trirutile-structured phases increased as the Ta content increased in a given region, and the end member ZnTiTa2O8 formed a single phase with the trirutile structure. The microwave dielectric properties were closely related to the crystal structures. A material with a near zero temperature coefficient of resonant frequency could be obtained for x=0.8, and its dielectric constant and quality factor (Qxf) were 40.5 and 41,000 GHz, respectively. (C) 2011 Elsevier B.V. All rights reserved.