'The Role of the Grain Boundary on the Resistivity of Pb(Fe 1/2 Nb 1/2 )O 3 at Room Temperature

The effect of changing sintering temperature on the grain boundary properties and the room temperature resistivity (?RT) of Pb(Fe1/2Nb1/2)O3 (PFN) was investigated. Monitering the temperature dependence of resistivity showed that the ?RT’s of 1050°C and 1150°C-sintered specimen were 1011OEcm and 104OEcm respectively, but the resistivity above 300°C became nearly identical. The previous model, that the low resistivity of PFN is due to the electron hopping between Fe2+ and Fe3+ driven by the reduction of PFN, couldn’t explain this phenomenon, and the reconsideration of the Fe reduction revealed that the difference of electron concentration between the 1050°C and 1150°C-sintered specimen couldn’t exceed one order of magnitude. The role of the grain boundary was introduced in order to account for this phenomenon.