Potential Barrier Behavior of BaTiO3–(Bi0.5Na0.5)TiO3 Positive Temperature Coefficient of Resistivity Ceramic
LENG Sen-Lin1**, SHI Wei1, LI Guo-Rong2, ZHENG Liao-Ying2
1Institute of Physics and Electronics Engineering, Tongren University, Tongren 554300 2Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050
Abstract：High-Curie-temperature (Tc) lead-free Y-doped 90 mol%BaTiO3–10 mol%(Bi0.5Na0.5)TiO3 ceramic with positive temperature coefficient of resistivity (PTCR) is prepared by the conventional solid state reaction in nitrogen atmosphere. The PTCR ceramic exhibits a room-temperature resistivity (ρ25) of ～500 Ω?cm and a high PTCR effect (maximum resistivity (ρmax)/minimum resistivity (ρmin)) of ～4.5 orders of magnitude. A capacitance-voltage approach is first employed to calculate the potential barrier (?) of the grain boundary of PTCR ceramic above Tc. It is found that the potential barrier changes from 0.17 to 0.77 eV as the temperature increases from 180 to 220°C, which is very close to the predictions of the Heywang–Jonker model, suggesting that the capacitance-voltage method is valid to estimate the potential barrier of PTCR thermistor ceramics.
2015, Vol. 32 
