Low-Loss Microwave Ceramics Based on Non-Stoichiometric Perovskites Ba(Co_1/3Nb_2/3)O₃ and Ba(Zn_1/3Nb_2/3)O₃

Abstract

The effect of both A-site and B-site non-stoichiometry on the microstructure and microwave dielectric properties of the perovskite niobates Ba(A ^{2 +} _1/3 Nb _2/3 )O ₃ (A ^{2 +} = Co, Zn) has been examined. Both the chemical composition of the ceramics and their sintering regimes have been shown to significantly influence the type and the amount of impurity phases which consecutively demonstrate a prevailing effect on the microwave dielectric loss. The highest magnitudes of the Qxf product have been obtained in the Co-deficient BCN (Qxf = 100 000 GHz) and Ba-deficient BZN (Qxf = 90 000 GHz) which both demonstrate noticeable amount of secondary Ba-rich phases.

Keywords:

• Dielectrics
• complex perovskites
• cation ordering
• quality factor

5. Acknowledgments

This work was partially supported by the NATO Grant under the NATO SfP project 980881: “Dielectric Resonators” of the NATO “Science for Peace” Program.