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Ba(Zn 1/3 Ta 2/3 )O 3 Ceramics for Microwave and Millimeter‐wave Applications
Author(s) -
Alexandru H. V.,
Ioachim A.,
Toacsan M. I.,
Nedelcu L.,
Banciu M. G.,
Berbecaru C.,
Voicu G.,
Jinga S.,
Andronescu E.
Publication year - 2009
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2008.04077.x
Subject(s) - analytical chemistry (journal) , materials science , ceramic , temperature coefficient , scanning electron microscope , dielectric , microwave , sintering , microstructure , atmospheric temperature range , perovskite (structure) , octahedron , grain size , mineralogy , crystallography , crystal structure , chemistry , metallurgy , composite material , physics , optoelectronics , chromatography , quantum mechanics , meteorology
The Ba(Zn 1/3 Ta 2/3 )O 3 (BZT) ceramic samples were prepared by solid‐state reaction and sintered in the range 1550–1650°C for 2 h. Several methods—X‐ray diffraction (XRD) and scanning electron microscopy (SEM)—were used for structural and morphological characterization. The unit cell distortion and the presence of the secondary phase content were studied by XRD. A long‐range order with a 2:1 ratio of Ta and Zn cations on the octahedral positions of the perovskite structure was noticed with the increase of the sintering temperature. SEM investigations revealed polyhedral well‐faceted grains and large grain size distribution. The dielectric properties in the microwave range were measured at room temperature and at 1 kHz on a large temperature interval (±150°C). The dielectric parameters were correlated with morphological and structural properties. Ceramic samples were annealed at 1410°C for 30 h to improve the microwave properties. The dielectric constant of BZT samples measured at 6 GHz and at 1 kHz was between 27 and 28 on the whole temperature range, that is, typical values for BZT material. The temperature coefficient of the resonance frequency at 6 GHz exhibits positive values less than 6 ppm/°C.