Departmental Papers (MSE)

Document Type

Journal Article

Date of this Version

July 2006

Comments

Copyright The American Ceramic Society. Reprinted from Journal of the American Ceramic Society, Volume 89, Issue 7, July 2006, pages 2271-2278.

Abstract

High Q ceramics of Ba3W2O9 (BW)-substituted Ba(Zn1/3Nb2/3) O3 (BZN) were prepared with a zero τf through the partial substitution of Zn by Ni and Co. The small concentrations of B-site vacancies introduced by the substitution of BW accelerated the kinetics and stability of the cation ordering and lowered the sintering temperature. Dense, zero τzf, ordered solid solutions such as 0.99Ba(Zn0.3Co0.7)1/3Nb2/3O3–0.01BW with εr=34.4 and Q×f=82 000 at ~8 GHz could be obtained after sintering at 1380°C for 5 h and annealing at 1300°C for 24 h. Partially ordered ceramics in the Zn/Co and Zn/Ni solid solutions show a large gradient in the ordering throughout the pellets, which produces a resonant frequency dependence of their Q×f value. The ordering gradient is associated with the increased constraints on the growth of the 1:2 ordered structure within the interior of larger and thicker pellets and can be minimized by extended annealing.

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Date Posted: 06 December 2006

This document has been peer reviewed.