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Far‐Infrared Reflection Spectra of Dielectric Ceramics for Microwave Applications
Author(s) -
Fukuda Koichi,
Kitoh Ryozo,
Awai Ikuo
Publication year - 1994
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.1151-2916.1994.tb06969.x
Subject(s) - dielectric , microwave , materials science , infrared , analytical chemistry (journal) , ion , reflection (computer programming) , infrared spectroscopy , ceramic , dispersion (optics) , crystal (programming language) , spectral line , optics , chemistry , optoelectronics , physics , organic chemistry , chromatography , quantum mechanics , computer science , composite material , programming language , astronomy
Far‐infrared reflection spectra of dielectric ceramics, BaSm 2 Ti 5 O 14 , BaTi 4 O 9 , and some pcrovskites such as Ba(Zn 1/3 Nb 2/3 )O 3 , have been measured at room temperature using a Fourier transform infrared spectrometer in order to investigate the effect of the crystal structure on the dielectric properties. As for perovskites, Sr(Zn 1/3 Nb 2/3 )O 3 and Sr(Mg 1/3 Nb 2/3 )O 3 , in which B site ions are ordered, were also measured. Reflectance data were analyzed by means of a factorized form of dielectric functions instead of the classical dispersion theory, and all of the spectra were well fitted. The values of dielectric constants and tan δ calculated from the reflectance data were in good agreement with resonant cavity measurements at 5 GHz. Furthermore, results of this study have shown that the main contribution to the microwave dielectric properties is caused by low‐frequency optically active modes located at 50 to about 300 cm −1 , and for perovskite structures it is suggested that the ordering of B site ions is significant in obtaining low dielectric losses.