Structure and microwave dielectric properties of BaLa4Ti 4O15

H. Zheng, D. I. Woodward, L. Gillie, I. M. Reaney

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


BaLa4Ti4O15 (BLT) is a compound with a Ti-deficient, layered perovskite-related structure. Dense BLT ceramics have been produced and their crystal structures and microstructures are investigated. The average macroscopic structure of BLT powder is considered to be hexagonal with space group, but there is some evidence in high-order x-ray diffraction peaks of asymmetry. Energy-dispersive x-ray analysis and Raman spectroscopy have illustrated that there is a heterogeneous distribution of constituent cations which may induce asymmetry as a result of the presence of two hexagonal phases of slightly different lattice parameter. Despite this inhomogeneity, BLT exhibits a microwave quality factor (Qf) of ∼44000 GHz, a relative permittivity (εr) of ∼45, and a temperature coefficient of resonant frequency (τf) of -2 ppm °C-1. In addition, anisotropy in the properties of the ceramic has been observed, with εr found to be larger when measured normal to the pressing direction.

Original languageEnglish
Article number001
Pages (from-to)7051-7062
Number of pages12
JournalJournal of Physics Condensed Matter
Issue number31
Publication statusPublished - 21 Jul 2006
Externally publishedYes


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