Tailoring order–disorder temperature and microwave dielectric properties of Ba[(Co0.6Zn0.4)1/3Nb2/3]O3 ceramics

Abstract

The order–disorder temperature (To–d) of Ba[(Co0.6Zn0.4)1/3Nb2/3]O3 ceramics was determined via X-ray diffraction, Raman spectroscopy and differential thermal analysis, respectively. To–d was determined to be between 1425 and 1450 °C by a quenching method. The endothermic peak in the DTA curve shows the order–disorder transition. B2O3 was applied to tune the densification temperature (Ts) and tailor the microwave dielectric properties. The ordering degree and unloaded quality factor (Qf) are improved when Ts is reduced to 1400 °C at B2O3 content of 0.25 mol%. Ts is further decreased and the ordering degree and Qf are decreased when B2O3 content is increased to 0.5 mol%. The dielectric constant (εr) and temperature coefficient of resonant frequency (τf) decrease slightly with increasing B2O3 content. The optimum microwave dielectric properties (i.e., εr = 34.0, Qf = 50,400 GHz, τf = 5.5 × 10−6/°C) are obtained for the Ba[(Co0.6Zn0.4)1/3Nb2/3]O3-0.25 mol% B2O3 ceramics sintered at a lower temperature.

Keywords

• Microwave dielectric ceramics
• Complex perovskites
• Order–disorder transition