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Investigation of Resistivity and Permittivity for (Ba,Pb)TiO 3 PTCR Ceramics
Author(s) -
Lai ChunHung,
Tseng TseungYuen
Publication year - 1994
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.1151-2916.1994.tb04613.x
Subject(s) - electrical resistivity and conductivity , condensed matter physics , dielectric , materials science , permittivity , curie temperature , temperature coefficient , arrhenius equation , activation energy , relative permittivity , ceramic , acceptor , chemistry , physics , composite material , optoelectronics , organic chemistry , quantum mechanics , ferromagnetism
A scheme to examine quantitatively the interdependence between the measured resistance and permittivity data for semiconducting (Ba,Pb)TiO 3 samples having Curie points above 300°C was developed based on the Schottky‐type potential barrier model. Specifically, the nonvanishing spontaneous polarization in the ferroelectric state was considered in terms of a useful parameter to explain the low resistivity below the Curie point. The resistivity derived from the measured permittivity shows a consistent temperature dependence with the dc measured one, i.e., the positive temperature coefficient of resistance (PTCR) characteristics. It is also observed that more satisfactory agreement can be achieved when the acceptor states are assumed to be distributed over a certain energy interval. The values of acceptor‐state densities thus obtained are found to be in excellent agreement with those extracted from the slope in the Arrhenius plots of resistivity vs l/( T ε m ), where T is the absolute temperature and ε m the dielectric constant. The validity of the present methodology is justified by obedience to the Curie–Weiss law for the calculated bulk dielectric constant.