NTC characteristic of SnSb0.05O2–BaTi0.8Fe0.2O3−δ composite materials

SnSb x O2 (x = 0.003, 0.01, 0.02, 0.05 and 0.07) ceramics and SnSb0.05O2–BaTi0.8Fe0.2O3-δ composite ceramics were prepared by using wet-chemical synthesis methods. The phases and related electrical properties of the ceramics were investigated. The results show that all the prepared ceramics have the effect of negative temperature coefficient (NTC) of resistivity over a wide temperature range. The room-temperature resistivities (ρ 25) and material constants (B 25/85) of the SnSb x O2 NTC ceramics increase with the Sb concentration increases. The B 25/85 of the ceramics can be enhanced obviously when a certain content of BaTi0.8Fe0.2O3-δ was added in SnSb x O2. The analysis of impedance spectra reveals that both grain and grain boundary contribute to the NTC effect of the ceramics. The conduction mechanisms combining the electron-hopping model and band conduction are proposed for the NTC effect in the SnSb0.05O2–BaTi0.8Fe0.2O3-δ composite ceramics.