Positive temperature coefficient of resistivity effects of semiconducting (Bi½ Na½) TiO3-CaTiO3-BaTiO3 ceramics sintered in air atmosphere

Abstract

Y3+-doped (Bi½ Na½) TiO3-CaTiO3-BaTiO3 (BNCBT) positive temperature coefficient of resistivity (PTCR) ceramics sintered in air atmosphere were investigated in this study. (Bi½ Na½) TiO3 (BNT) component can remarkably increase the onset temperature Tc of PTCR ceramics with the expense of the resistivity R25 increase. CaTiO3 (9–27 mol%) component can decrease the resistivity, and adjust the effects of BNT phase on the Tc point. For the sample containing 3 mol% CaTiO3, Tc raises from 122 °C to 153 °C when only 0.6 mol% BNT added, while for the ones with higher CaTiO3 content (9–27 mol%), Tc is only increased by a rate of 8–9 °C/1.0 mol% BNT. The effects of BNT and CaTiO3 components on \( \frac{{{R_{25}}}}{{{R_{\min }}}} \) (negative temperature coefficient effect) are also discussed.