Departmental Papers (CBE)

Influence of Non-Stoichiometry on the Structure and Properties of Ba(Zn1/3Nb2/3)O3 Microwave Dielectrics: II. Compositional Variations in Pure BZN

Hui Wu, University of Pennsylvania
Peter K. Davies, University of Pennsylvania

Document Type Journal Article

Postprint version. Copyright The American Ceramic Society. Reprinted from Journal of the American Ceramic Society, Volume 89, Issue 7, July 2006, pages 2250-2263.


The formation of non-stoichiometric cubic perovskite solid solutions based on BaZn1/3Nb2/3O3 (BZN) was examined along 10 different directions in the BaO–ZnO–Nb2O5 ternary system. Limited ranges of non-stoichiometry were observed along several pseudo-binaries and the BZN structure can accommodate a variety of different types of defects. Although the deviations from stoichiometry are quite small, typically ~1 mole%, they induce large changes in the extent and stability of the 1:2 B-site ordering, the sintering and microstructure, and the dielectric loss properties. The highest Q×fs (~110 000 at 8 GHz) in the system, which coincide with the highest degree of order, were located in two regions along the BZN–Ba5Nb4O15 and BZN–BaNb2O6 lines. The results of this study provide an explanation for the large variations in crystal structure and Q×fs previously reported for BZN and other related systems (e.g., Ba(Zn1/3Ta2/3)O3), and demonstrate that non-stoichiometric starting compositions provide a route to the highest Q values.


Date Posted: 05 December 2006

This document has been peer reviewed.