Dielectric and ferroelectric properties of Si sub(4)CaSmTi sub(3)Nb sub(7)O sub(30) with tetragonal tungsten bronze structure

Sr sub(4)CaSmTi sub(3)Nb sub(7)O sub(30) ceramics are synthesized and indexed as tetragonal tungsten bronze structure. The dielectric behavior and ferroelectric nature are investigated. Three dielectric anomalies are observed. The phase transition is a displacive phase transition with some diffusive...

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Bibliographic Details
Published in:Chinese physics B 2014-09, Vol.23 (9), p.097701-1-097701-4
Main Authors: Gong, Gao-Shang, Fang, Yu-Jiao, Huang, Shuai, Yin, Chong-Yang, Yuan, Song-Liu, Wang, Li-Guang
Format: Article
Language:English
Subjects:
BRONZES
Cations
CERAMICS
Dielectrics
Displacement
ELECTRICAL PROPERTIES
Ferroelectric materials
Ferroelectricity
INSULATION (ELECTRICAL)
Phase transformations
Polarization
Tungsten bronze
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Summary:Sr sub(4)CaSmTi sub(3)Nb sub(7)O sub(30) ceramics are synthesized and indexed as tetragonal tungsten bronze structure. The dielectric behavior and ferroelectric nature are investigated. Three dielectric anomalies are observed. The phase transition is a displacive phase transition with some diffusive characteristics, which indicates possible compositional variations within the materials on the microscopic scale. The weak distortion disappears in cooling process for differential scanning calorimetry measurement, and the large depression of Curie-Weiss temperature T sub(0) indicates the difficulty in forming macroferroelectric domain. The ferroelectric nature in these filled tungsten bronze niobates originates from the off-center displacement of B-site cations, but they are primarily dominated by A-site cation occupation. Both the radius and the valence of Al-site cations play an important role on ferroelectric properties of the filled tungsten bronze compounds. Existence of spontaneous polarization with a remanent polarization of 0.16 mu C/cnr a coercive field of E sub(c) = 11.74 kV/cm confirms the room-temperature ferroelectric nature of Sr sub(4)CaSmTi sub(3)Nb sub(7)O sub(30) ceramics.
ISSN:1674-1056
1741-4199
DOI:10.1088/1674-1056/23/9/097701