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Improvement of Microwave Dielectric Characteristics in SrLaAlO 4 Ceramics by Ca Substitution
Author(s) -
Peng Li Qin,
Mao Min Min,
Chen Xiang Ming
Publication year - 2010
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.1551-2916.2010.03990.x
Subject(s) - analytical chemistry (journal) , ceramic , dielectric , materials science , microwave , chemical composition , temperature coefficient , phase (matter) , diffraction , permittivity , relative permittivity , solid solution , mineralogy , dielectric loss , x ray crystallography , chemistry , optics , metallurgy , composite material , physics , chromatography , optoelectronics , organic chemistry , quantum mechanics
The improvement in microwave dielectric characteristics by Ca substitution in SrLaAlO 4 ceramics together with the stability of K 2 NiF 4 structure were investigated. X‐ray diffraction analysis and the scattering electron images combined with EDS analysis indicated that the matrix phase was a solid solution with a composition represented by the chemical formula Sr 1− x Ca x LaAlO 4 in the entire range of 0≤ x ≤0.9, and minor amount of LaAlO 3 secondary phase was detected only in the composition of x =0.8 and 0.9. The relative permittivity increased slightly with increasing x , while the temperature coefficient of resonant frequency was tuned from −33.9 to −14.7 ppm/°C. The significant improvement of Qf value was achieved in the present ceramics with increasing x and reached the maximum at x =0.4, but it turned to decrease for x >0.4. The best combination of microwave dielectric characteristics was achieved at x =0.4: ɛ r =18.1, Qf =150 500 GHz, and τ f =−26.2 ppm/°C.