Calculations and modeling of grain-boundary acceptor states for (Ba,Pb)TiO3 positive temperature coefficient ceramics

Authors:
Publisher website
Google Scholar
Abstract
The electrical properties of high‐Curie‐point positive temperature coefficient of resistance ceramics of composition Ba0.497Pb0.5La0.003Ca0.005Ti0.995O3 prepared from commercial BaTiO3 powder were studied. The acceptor‐state energy and acceptor‐state density were determined from the calculated ρmax vs Tmax plot, where ρmax and Tmax are the resistivity and temperature corresponding to the maximum in resistivity. These two parameters, combined with the effect of nonvanishing spontaneous polarization below the Curie point, were treated quantitatively to demonstrate the dependence of measured resistivity ρdc on the measured permittivity εm. The obtained values of potential barrier height and acceptor‐state density based on the procedure above were found to be in excellent agreement with those extracted from the slope in the Arrhenius plots of resistivity versus 1/(Tεm), where T is the absolute temperature. Also, the deviation of the measured dielectric constant εm from the Curie–Weiss law’s prediction was explained by the narrowing of the grain‐boundary barrier layers.

This publication has 22 references indexed in Scilit: