Effect of Donor Dope Ions, Compaction Pressures and Sintering Temperatures on PTCR and Dielectric Properties of BaTiO3

Donor doped BaTiO3 is a well known PTCR material. Many PTCR theories have been written but none of them can completely explain the PTCR property. In this work, BaTiO3 samples doped with Sb, La, Nb and Pb ions and compacted under various uniaxial pressures were examined. Results show that Sb and La-doped BaTiO3 have PTCR properties corresponding to Heywang and Jonker models to a greater degree than Nb-doped BaTiO3. Moreover, it was found that La and Nb-doped Ba1-xPbxTiO3 samples sintered at 1000-1100 degrees C have good PTCR properties while samples of the same composition sintered at 1150-1200 degrees C have fair to poor PTCR properties. The PTCR properties in these materials do not correspond to Heywang and Jonker models. The resistivity change in these materials at Curie's point is relatively lower than the resistivity change at other temperatures.