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Giant Permittivity of a Bismuth Zinc Niobate–Silver Composite
Author(s) -
George Sumesh,
James Jose,
Sebastian Mailadil Thomas
Publication year - 2007
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.1551-2916.2007.01935.x
Subject(s) - materials science , dielectric , permittivity , bismuth , volume fraction , composite number , composite material , ceramic , dielectric loss , high κ dielectric , sintering , percolation (cognitive psychology) , relative permittivity , mineralogy , analytical chemistry (journal) , metallurgy , chemistry , optoelectronics , neuroscience , biology , chromatography
Bismuth zinc niobate–Silver (BZN–Ag) composites were prepared by the solid‐state ceramic route. The sintering temperature of BZN–Ag composites was lowered to 850°C/2 h. The structure and surface morphology of the composites were investigated using X‐ray diffraction and optical microscope. The dielectric and conducting properties of the composites were systematically investigated with the volume fraction of silver in the frequency range from 1 KHz to 1 MHz. The dielectric constant of the composite increases with the silver content and is in good agreement with the power law below the percolation limit. Addition of 0.14 volume fraction of silver increases the dielectric constant of BZN+2 wt% B 2 O 3 from 150 to 2350 at 1 MHz. However, 15 volume percentage of silver loading results in a large permittivity of (ɛ r )≈10 5 with a low dielectric loss (tan δ≈10 −2 ) at 1 MHz. Subsequent increase in silver loading decreases the dielectric constant. The BZN–B 2 O 3 –Ag composite with large permittivity may find applications in electromechanical and tunable devices.