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Microwave Dielectric Properties of Hexagonal 12R‐Ba 3 LaNb 3 O 12 Ceramics
Author(s) -
Rawal Ritesh,
Feteira Antonio,
Hyatt Neil C.,
Sinclair Derek C.,
Sarma Kumaravinothan,
Alford Neil McN.
Publication year - 2006
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.1551-2916.2005.00664.x
Subject(s) - ceramic , temperature coefficient , sintering , materials science , relative permittivity , microwave , dielectric , microstructure , hexagonal crystal system , permittivity , analytical chemistry (journal) , band gap , mineralogy , phase (matter) , mixed oxide , relative density , oxide , crystallography , composite material , metallurgy , optoelectronics , physics , chemistry , chromatography , quantum mechanics
The dielectric properties of dense ceramics of the n =0 member of a newly identified homologous series Ba 3+ n LaNb 3 Ti n O 12+3 n , where n =0, 1, and 2, are reported. Single‐phase powders can be obtained from the mixed‐oxide route at 1350°C and dense ceramics (>97% of the theoretical X‐ray density) with uniform microstructures (3–5 μm) can be obtained by sintering in air at 1500°C. The ceramics are excellent dc insulators with a band gap >2.6 eV that resonate at microwave frequencies with a relative permittivity, ɛ r ∼44, a quality factor, Q × f r , of ∼9000 at f r ∼5.5 GHz and a temperature coefficient of resonant frequency, TC f ,∼−100 ppm/K.