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Microwave Dielectric Properties of Gallium‐Doped Hexagonal Barium Titanate Ceramics
Author(s) -
Feteira Antonio,
Sarma Kumaravinothan,
Alford Neil McN.,
Reaney Ian M.,
Sinclair Derek C.
Publication year - 2003
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2003.tb03330.x
Subject(s) - ceramic , materials science , barium titanate , permittivity , relative permittivity , dielectric , sintering , pellets , gallium , mineralogy , perovskite (structure) , analytical chemistry (journal) , doping , microwave , mixed oxide , relative density , oxide , composite material , optoelectronics , metallurgy , chemistry , crystallography , organic chemistry , physics , quantum mechanics
High‐permittivity and low‐loss ceramics with composition BaTi 0.92 Ga 0.08 O 2.96 have been prepared in the BaO–Ga 2 O 3 –TiO 2 system using the mixed‐oxide route. This compound forms as the hexagonal polymorph (6 H ) of BaTiO 3 with the space group P 6 3 / mmc . The dielectric properties of dense ceramics have been studied, at microwave frequencies, with the ceramics fired at 1450°C under flowing oxygen gas; the results are a relative permittivity, ɛ r , of ∼74 and a quality factor, Q · f r , of ∼7815 at 5.5 GHz. The quality factor is strongly influenced by the sintering conditions (temperature and atmosphere), whereas the relative permittivity is not influenced significantly by ceramic processing for pellets ≥93% of the theoretical X‐ray density. To our knowledge, this is the first report of microwave dielectric resonance in a perovskite‐type BaTiO 3 ‐based ceramic.