PTCR-NTCR composite behavior of bismuth titanate ceramics

In this paper, we report the synthesis of bismuth titanate (Bi4Ti3O12, BiT) ceramics by solid state reaction method. Structural and electrical properties were studied for phase and temperature coefficient of resistance, respectively. A single phase orthorhombic structure of bismuth titanate was observed. Sample shows mixed temperature coefficient of resistance behavior, exhibiting negative TCR (NTCR) in the beginning and later positive TCR (PTCR). This kind of unusual (σ-T) behavior was accounted for core-shell microstructure. The result of TGA-DSC showed the crystallization temperature of these ceramic samples.