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Structure and microwave dielectric properties of ALn 4 (MoO 4 ) 7 (A = Ba, Sr, Ca, Ln = La, Pr, Nd, and Sm) ceramics
Author(s) -
Dhanya Johnson,
Sarika Padinjare V.,
Naveenraj Rajaram,
Suresh Elattuvalappil K.,
Ratheesh Ravendran
Publication year - 2019
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/ijac.13178
Subject(s) - materials science , ceramic , raman spectroscopy , microstructure , analytical chemistry (journal) , scanning electron microscope , spectroscopy , powder diffraction , dielectric , mineralogy , crystallography , metallurgy , composite material , optics , chemistry , physics , optoelectronics , chromatography , quantum mechanics
ALn 4 (MoO 4 ) 7 (A = Ba, Sr, Ca, Ln = La, Pr, Nd, Sm) ceramics are prepared by solid state ceramic route and the structural properties have been studied using powder X‐ray diffraction and laser Raman spectroscopy. All the ceramics under study are phase pure except BaLn 4 (MoO 4 ) 7 (Ln = Pr, Nd, Sm). Scanning electron micrographs of the sintered ceramics show closely packed microstructure with phase homogeneity. BaLa 4 (MoO 4 ) 7 ceramic has a maximum density of 4.5 g/cm 3 at 710°C together with ԑ r = 11.8, Q u x f = 39 300 GHz, and τ f = −68 ppm/ o C. SrLa 4 (MoO 4 ) 7 ceramic exhibited a maximum density of 4.4 g/cm 3 , ԑ r = 11.7, Q u x f = 44 200 GHz, and τ f = −83 ppm/ ° C at 740°C whereas CaLa 4 (MoO 4 ) 7 ceramic possess a maximum density of 4.2 g/cm 3 , ԑ r = 11.4, Q u x f = 30 200 GHz and τ f = −90 ppm/ o C at 750°C at microwave frequencies. The chemical compatibility of the BaLa 4 (MoO 4 ) 7 , SrLa 4 (MoO 4 ) 7 and CaLa 4 (MoO 4 ) 7 ceramics with silver electrode have been studied using powder X‐ray diffraction of the co‐fired samples and is further examined with energy dispersive X‐ray spectroscopy.