The influence of soaking time at 1200°C on the temperature coefficient of resistivity (TCR) of semiconducting barium titanate ceramics has been investigated. It is found that soaking duration has influence on the room‐temperature resistivity, the maximum resistivity, the temperature (Tmax) at which the maximum resistivity appears, and TCR of the positive temperature coefficient of resistivity (PTCR) ceramics. The increased room‐temperature resistivity with the increase of soaking time is contributed mainly by the increase of grain boundary resistivity examined by the complex‐plane impedance method. The obtained surface acceptor density (Ns) by capacitance–voltage measurement is found to increase with the soaking duration. The higher Ns contributes to higher built‐in potential and results in lower Tmax and higher maximum resistivity. Therefore, the increased surface acceptor density from increasing the soaking time at 1200°C increases the temperature coefficient of resistivity of PTCR ceramics.
|Number of pages||4|
|Journal||Journal of the American Ceramic Society|
|State||Published - 1 Jan 1994|