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Dielectric Properties of Strontium Titanate Solid Solutions Containing Niobia
Author(s) -
TIEN T. Y.,
MORATIS C. J.
Publication year - 1967
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.1151-2916.1967.tb15141.x
Subject(s) - solid solution , dielectric , materials science , tetragonal crystal system , niobium , strontium titanate , perovskite (structure) , activation energy , lattice constant , relaxation (psychology) , octahedron , mineralogy , analytical chemistry (journal) , crystallography , crystal structure , diffraction , chemistry , metallurgy , psychology , social psychology , physics , optoelectronics , chromatography , optics
SrTiO 3 solid solutions containing Sr 0.5 NbO 3 were studied by X‐ray diffraction and dielectric measurements. Single‐phase perovskite solid solutions were formed up to the composition containing 30 mole % Sr 0.5 NbO 3 . The addition of niobium resulted in a symmetry change from cubic (SrTiO 3 ) to tetragonal (solid solution) and the c/a ratio increased with increasing niobium content. The dielectric constant for the solid solutions was lower than that for SrTiO 3 . Pronounced dielectric relaxation peaks and dispersion in permittivity were observed for the composition 7SrTiO 3 :3Sr 0.5 NbO 3 . The activation energy for the relaxation process is about 0.42 ev. It is suggested that the existence of the A‐site vacancy in the perovskite ABO 3 lattice introduced by the niobium substitution distorts the oxygen octahedra, producing more than one possible “noncentral” site for the Ti 4+ ion. The relaxation arises from the thermal motion over potential barriers separating these alternative sites.