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Correlation Between Structural Characteristics and Microwave Dielectric Properties of Scheelite Ca 1− x Cd x MoO 4 Solid Solution
Author(s) -
Rama Rao S. D.,
Roopas Kiran S.,
Murthy V. R. K.
Publication year - 2012
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.1551-2916.2012.05317.x
Subject(s) - polarizability , dielectric , analytical chemistry (journal) , tetragonal crystal system , temperature coefficient , rietveld refinement , chemistry , valence (chemistry) , microwave , ionic bonding , crystallography , ion , materials science , mineralogy , crystal structure , molecule , physics , optoelectronics , organic chemistry , chromatography , quantum mechanics , composite material
Ca 1− x Cd x MoO 4 ( x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) ceramics were prepared by solid‐state reaction method. Tetragonal scheelite structure with I 4 1 / a space group was observed in all these compositions. Microwave dielectric properties such as quality factor ( Q × f ), dielectric constant (ε r ), and temperature coefficient of resonant frequency ( τ f ) were measured in the microwave frequency range. Rietveld refinement was performed on all these compositions and bond valences of A ‐, B ‐site cation, and oxygen were calculated. Influence of these structural parameters on the microwave dielectric properties was examined. Q × f was correlated with the average covalence of A ‐, B ‐site cations. The variation in ε r was explained with ionic polarizability of Cd +2 ions. The deviation of observed polarizability from theoretical polarizability and τ f of all these compositions were explained with oxygen bond valence. The well‐sintered Ca 1− x Cd x MoO 4 ceramics showed highly promising microwave dielectric properties ( ε r = 8–10, Q × f = 46000–53000 GHz and τ f = −22 to −57 ppm/ ° C).