Electrical conductivity and temperature sensitivity of Cu/Mo co-modified YFeO3 ceramics

Abstract

To develop a new kind of thermistor with the negative temperature coefficient (NTC) behaviour, the Cu/Mo co-doped YFeO3 based ceramics were prepared by wet-chemical synthesis and sintering at 1300°C. The orthorhombic perovskite structure was identified in all ceramics by XRD analysis. The possible valence states of Fe, Cu and Mo in the doped YFeO3 compounds were examined by X-ray photoelectron spectroscopy. By adjusting the concentration of Cu- and Mo-ions, the room temperature resistivity (ρ25) and temperature-sensitive constant (B25/85) can be modified from 1.13×103 to 3.09×105 Ω•cm and 3000 to 7000K, respectively. The complex impedances at various temperatures (from 25 to 150°C) are tested and analysed. The results show that both grain and grain boundary exhibit the NTC characteristics. The electrical conduction mechanisms composing of polaron hopping conduction and band conduction were proposed in the YFeO3 based ceramics.

Keywords

• cu/mo co-doped yfeo3
• electrical properties
• temperature sensitivity
• conduction mechanism