Structural ordering and dielectric properties of Ba3CaNb2O9-based microwave ceramics

Author(s)

Rodrigues, J. E. F. S. ; Castro, P. J. ; Pizani, P. S. ; Correr, W. R. ; Hernandes, A. C.

• Document type: Journal article
• Source: CERAMICS INTERNATIONAL; v. 42, n. 16, p. 18087-18093, DEC 2016.
• Web of Science Citations: 7

Abstract

Ba3CaNb2O9 is a 1:2 ordered perovskite which presents a trigonal cell within the D-3d(3) space group. Dense ceramics of Ba3CaNb2O9 were prepared by the solid-state reaction route, and their microwave dielectric features were evaluated as a function of the sintering time. From Raman spectroscopy, by using group theory calculations, we were able to recognize the coexistence of the 1:1 and 1:2 ordering types in all samples, in which increasing the sintering time tends to reduce the 1:1 domain, leading to an enhancement of the unloaded quality factor. We concluded that this domain acts as a lattice vibration damping, consequently raising the dielectric loss at microwave frequencies. The best microwave dielectric parameters were determined in ceramics sintered at 1500 degrees C for 32h: epsilon' similar to 43; Q(u) x f(r) = 15,752 GHz; tau(f) similar to 278 ppm degrees C-1. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved. (AU)

• FAPESP's process: 08/57872-1 - National Institute for Materials Science in Nanotechnology
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC