BaTiO3 and SrBiO2.5 two phase system NTC thermistors

BaTiO3-based materials doped with SrBiO2.5 only show negative temperature coefficient effect over a wide temperature range. X-ray diffraction analysis displays that major phases present in the sintered bodies were the Ba0.5Sr0.5TiO3 compounds with a cubic structure and the BaBiO3 compounds with a monoclinic structure. The mean grain size of samples remains unchanged with an increase from 20 to 50 in SrBiO2.5 content. The values of ρ25 and B25/125 constants of thermistors decreased with an increase in SrBiO2.5 content. The resistivity measured at other temperatures showed basically the same behavior as that at room temperature, irrespective of the measuring temperature.