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Microwave Dielectric Properties of Ba 2 Ca 1− x Sr x WO 6 Double Perovskites
Author(s) -
Zhou Yuanyuan,
Meng Siqin,
Wu Hongchao,
Yue Zhenxing
Publication year - 2011
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.1551-2916.2011.04450.x
Subject(s) - monoclinic crystal system , dielectric , temperature coefficient , materials science , ceramic , perovskite (structure) , analytical chemistry (journal) , microwave , mineralogy , phase (matter) , trigonal crystal system , crystal structure , crystallography , chemistry , metallurgy , composite material , optoelectronics , organic chemistry , chromatography , physics , quantum mechanics
Ba 2 Ca 1− x Sr x WO 6 ( x =0–1) microwave dielectric ceramics have been prepared using the two‐step solid‐state reaction method. The substitution of Sr 2+ for Sr 2+ can effectively lower the densification temperature of the ceramics from 1500° to 1200°C. Single‐phase ceramics with double perovskite structures were obtained, and structural transitions occurred in Ba 2 Ca 1− x Sr x WO 6 via the phase sequence: cubic→rhombohedral→monoclinic with an increase of x . The microwave dielectric properties of the Ba 2 Ca 1− x Sr x WO 6 ceramics can be effectively tuned by tailoring x . The dielectric constant (ɛ r ) remains almost unvaried, the quality factor ( Q × f ) decreases monotonically, and the temperature coefficient of resonant frequency (τ f ) changes in sign with the increase of x . A good combination of the microwave dielectric properties was obtained for Ba 2 Ca 0.975 Sr 0.025 WO 6 sintered at 1250°C: ɛ r =23.9, Q × f =80 200 GHz, and τ f =+18 ppm/°C.