Materials (Apr 2024)
(Ba<sub>0.55</sub>Sr<sub>0.45</sub>)<sub>1−x</sub>La<sub>x</sub>Ti<sub>1.01</sub>O<sub>3</sub>-Bi<sub>0.5</sub>Na<sub>0.5</sub>TiO<sub>3</sub> Positive Temperature Coefficient Resistivity Ceramics with Low Curie Temperature (~−15 °C)
Abstract
Positive temperature coefficient of electrical resistivity (PTCR) materials with low Curie temperature have been paid increasing attention lately. In this study, PTCR materials with a Curie temperature of approximately −15 °C were investigated by La3+ doping Ba0.55Sr0.45TiO3 ceramics. It could be expected to meet the requirements of thermal management systems for low-temperature control. In addition, a trace amount of Bi0.5Na0.5TiO3 (BNT) was employed to improve the resistivity and the PTCR performance. A significant PTCR effect was achieved with a high resistivity jump of nearly four orders of magnitude, a high temperature coefficient of ~28.76%/°C, and a narrow transition temperature span of 22 °C in the (Ba0.55Sr0.45)0.99875La0.00125Ti1.01O3-0.0025Bi0.5Na0.5TiO3 ceramics. The PTCR enhancement mechanism of BNT is discussed.
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