The relationship between PTCR effect and donor content in Yb-doped BaTiO3 ceramics

Trivalent rare earth can occupy either Ba site or Ti site depending on its size and Ba/Ti ratio. Sintered in the air, semiconducting BaTiO3 ceramics doped by Yb2O3 could not be obtained in previous report. However, it could be obtained in case of the BaTiO3 as starting raw materials in this study. The sample with the minimum resistivity of about 35Omega.cm could be obtained when the content of Yb2O3 reached around 0.3mol%. The relationship between PTCR effect and donor content was also studied. In the case of other impurities free, the resistance jumping of the BaTiO3 ceramics decreases with the donor doping level increasing. Thus, the piling up of excess donors at grain boundary cannot enhance the PTCR effect.