The PTCR effect in BaTiO3 ceramics modified by donor dopant

The PTCR effect of BaTiO3-based ceramics is influenced severely by either impurities or the process. The influence of Ce3+, Sm3+ and Yb3+ on the PTCR effect was studied. In order to exclude other influential factors, the ceramics was only modified by donor dopant using high purity raw materials. It was found that, in each group of these donor doped samples, the RT resistance decreased with donor content in low doping level, after it reaches a minimum, and increases rapidly at high doping level; the PTCR effect decreased with donor content irrespective of the doping level.