Crystal structure and microwave dielectric properties of (Zn1−xCox)TiNb2O8 ceramics

Abstract

The crystal structure and microwave dielectric properties of (Zn1−xCox)TiNb2O8 ceramics have been investigated. The results showed that the (Zn1−xCox)TiNb2O8 ceramics contained two main phases: (Zn,Co)TiNb2O8 phase and (Zn,Co)0.17Nb0.33Ti0.5O2 phase. The microwave dielectric properties of the (Zn1−xCox)TiNb2O8 ceramics were strongly affected by the change of crystal structure of each phase. The (Zn1−xCox)TiNb2O8 (x=0.1, 0.2, 0.3, 0.4) ceramics were sintered at temperatures ranging from 1025 to 1125°C for 4h. With the increase of Co content, the amount of (Zn,Co)0.17Nb0.33Ti0.5O2 phase increased, resulting in the increase of the dielectric constant (εr), decrease of the Q×f value and the temperature coefficient of resonant frequency (τf) moving to the positive direction. The excellent microwave dielectric properties of εr=35.93, Q×f=35,125GHz, τf=0ppm/°C were obtained for the (Zn1−xCox)TiNb2O8 ceramics (x=0.3) sintered at 1075°C for 4h. The relatively low sintering temperature (<1080°C) and high dielectric properties in microwave range make these ceramics promising for application in electronics.