The PTCR effect of Ag+-modified strontium–lead titanate semiconducting ceramics doped with excess PbO

Y-doped Sr0.5Pb0.5TiO3 semiconducting ceramics were fabricated by adding excess PbO and controlling the sintering conditions. Their room temperature resistivity (ρRT) is 101 Ω cm and there is a jump of about five orders of magnitude in resistivity, showing the positive temperature coefficient of resistance (PTCR) effect. Adding Ag+ increases both the ρRT and the PTCR effect. Ag metal particles were observed to segregate in the 1.0 mol% Ag+-doped composition. The influences of excess PbO and Ag+ on the electrical properties of (Sr, Pb)TiO3-based semiconducting ceramics were discussed.