Room-temperature resistivities and PTCR properties of er-doped (Ba,Sr,Ca)TiO 3

Abstract

The effects of substitution of Sr and Ca at Ba sites on the positive temperature coefficient of resistance (PTCR) characteristics of Er-doped BaTiO 3 have been studied. In (Ba 0.996-xSr xEr 0.004) 0.997 TiO 3 system, the room-temperature resistivity (ρ 25) and temperature coefficient of resistance (TCR,α) decreased with increasing Sr content. As the SrO content was increased, the Curie temperature shifted to lower temperatures by 2.6 °C/mol%. The room-temperature resistivity also decreased with increasing CaO content in (Ba 0.996-yCa yEr 0.004) 0.997TiO 3. However, the shift in the Curie point was negligibly small with increasing CaO content. The system co-doped with 10 mol% SrO and 10 mol% CaO, (Ba 0.796Sr 0.10Ca 0.10Er 0.004) 0.997TiO 3, showed the lowest room-temperature resistivity (3.5 Ω-cm ).