Single grain boundary characterization of Nb-doped SrTiO3 bicrystals usingac four-point impedance spectroscopy

AC four-point impedance spectroscopy has been applied to Nb-doped SrTiO3 bi crystals. Due to the simplified geometry and highly conductive bulk of the bicrystal, the reference impedance of the electrode was significantly reduc ed, validating the applicability of ac four-point impedance spectroscopy fo r electroceramics. DC current-voltage characteristics without any interfere nce due to electrodes confirmed these ac measurements. Using ac four-point impedance spectroscopy, grain boundary contributions are isolated and the c orresponding grain boundary thickness and resistivity are estimated. (C) 20 00 American Institute of Physics. [S0003-6951(00)00218-7].