Structural properties of CaTi1−x(Nb2/3Li2/3)xO3−δ (CNLTO) and CaTi1−x(Nb1/2Ln1/2)xO3 (Ln=Fe (CNFTO), Bi (CNBTO)), modified dielectric ceramics for microwave applications

Autor: Francisco Nivaldo Aguiar Freire, Rodrigo Carvalho Souza Costa, Juciê de Sousa Almeida, Antonio Sergio Bezerra Sombra, M Santos, José Marcos Sasaki, A. D. S. Bruno Costa, R. S. T. M. Sohn
Rok vydání: 2009
Předmět:
Zdroj: Physica B: Condensed Matter. 404:1409-1414
ISSN: 0921-4526
DOI: 10.1016/j.physb.2008.12.037
Popis: This paper presents an investigation of the structural characteristics of Nb 1/2 Bi 1/2 (CNBTO), Nb 1/2 Fe 1/2 (CNFTO) and Nb 2/3 Li 1/3 (CNLTO) substitution into the B-site of calcium titanate ceramics. The modified CaTiO 3 (CTO) ceramics were prepared by the conventional solid-state method. The compounds were investigated, by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDXS). The X-ray analysis shows that all samples have an orthorhombic structure. The refinement analysis of all samples were also performed and discussed in this paper. For all studied samples, a Raman mode at 805 cm −1 was detected and its intensity increases as the substitution increases. The dielectric permittivity and loss at microwave frequencies (MW) were investigated. The CNLTO phase, present the highest dielectric constant ( k =35.8) at 3.9 GHz with loss (tg α =7×10 −3 ). The lowest value of k =25.7 ( f =4.8 GHz) and tg α =3×10 −3 , was obtained for the CNFTO phase. These measurements confirm the possible use of such material for microwave devices like dielectric resonator antennas.
Databáze: OpenAIRE
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