Chemistry and physics of semiconducting BaTiO3 based PTCR ceramics [for sensors]

For fifty years, the semiconducting PTCR ceramics have been developed to be one of the most important sensor groups, not only used as one kind of conditional physical sensor but also as new prospective chemical sensors. Defect structure, formation and diffusion of the semiconducting BaTiO₃ are the necessary condition for the resistivity anomalous with PTC. The adsorption and desorption of gas on the ceramic surface are two sufficient premises, particularly in terms of defect chemistry in semiconducting BaTiO₃ ceramics and were described.