Abnormal Behavior of B_2O_3 Vapor Dopants in BaTiO_3 Based PTCR Ceramics

The PTCR (Positive Temperature Coefficient Resistivity) effect of BaTiO3 based semiconducting ceramics is usually allied to the donor or acceptor. B2O3 with high vapor pressure at high temperatures can be used as vapor dopants. The behavior of B2O3 vapor dopants was studied in BaTiO3 based semiconducting ceramics. The dramatic results show that the resistivity jumping of the samples is improved distinctly, in the mean time, the room temperature resistivity is also increased. The enhancement of the PTCR effect of the samples doped with B2O3 vapor is possibly associated with the interstice of boron ion and barium vacancy or their related composite defects.