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Diffuse Phase Transition of Tantalum‐Bearing Strontium Barium Niobate
Author(s) -
Tsurumi Takaaki,
Hoshino Yoshio
Publication year - 1989
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.1151-2916.1989.tb06114.x
Subject(s) - strontium barium niobate , tantalum , strontium , dielectric , materials science , phase transition , barium , curie temperature , condensed matter physics , relaxation (psychology) , dielectric loss , phase (matter) , mineralogy , nuclear magnetic resonance , chemistry , ferroelectricity , physics , optoelectronics , ferromagnetism , psychology , social psychology , organic chemistry , metallurgy
The dielectric constants, ε′ and ε″, of tantalum‐bearing strontium barium niobate (SBNT) ceramics were measured as functions of temperature and frequency. The phase transition of SBNT became ambiguous by adding Ta and the apparent Curie temperature determined from the maximum of ε′ had a linear relation with the axial ratio c/a. A dielectric loss peak was observed in the phase transition region of SBNT, and its peak frequency increased with temperature. The loss peak was attributed to dielectric relaxation by the jump between two states with different polarizing directions as a preliminary phenomenon of the phase transition. A model based on the local variation from one unit cell to the next rather than the macroscopic compositional fluctuation in the crystal was proposed for the mechanism of diffuse phase transition.