Electrical properties of BaTiO3-based NTC thermistors doped by BaBiO3 and La2O3

In our research it has been firstly found that BaTiO3 materials doped with BaBiO3 only show negative temperature coefficient effect over a wide temperature range. Major phases present in the sintered bodies are BaTiO3 compounds with a perovskite structure and BaBiO3 compounds with a monoclinic structure. Also, at a given BaTiO3 and BaBiO3 content, the influence of La2O3 content on the microstructure and electrical properties has been investigated. The mean grain size of samples decreases with an increase in La2O3 content. However the mean grain size remains unchanged with a further increase in La2O3 content when the La2O3 content in material is more than 0.20. As the amount of La2O3 in BaTiO3-based ceramics thermistors increases, the resistivity decreases to a minimum value and then slowly increases again.