Characterization of negative temperature coefficient of resistivity in (Sn1-x Ti x )0.95Sb0.05O2 (x aparts per thousandcurrency sign 0.1) ceramics

Sb-doped SnO2-based ceramics substituted by a trace of titanium, (Sn1-x Ti (x) )(0.95)Sb0.05O2 (x a parts per thousand currency sign 0.1), were prepared through a wet chemical process polymerized with polyvinyl alcohol. The phase component and related electrical properties of the ceramics were investigated. The results show that all the ceramics have the tetragonal rutile-type SnO2 crystalline lattice and show typical effect of negative temperature coefficient (NTC) of resistivity. The room-temperature resistivities and NTC material constants can be adjusted widely by changing the Ti content in the ceramics. The investigations by analyzing the electrochemical impedance spectra at various temperatures show that both grain effect and grain-boundary effect contribute to the NTC feature of the ceramics. The conduction mechanisms combining the electron-hopping model and band conduction are proposed for the NTC effect in the ceramics.