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

Abstract

AC four-point impedance spectroscopy has been applied to Nb-doped SrTiO3 bicrystals. Due to the simplified geometry and highly conductive bulk of the bicrystal, the reference impedance of the electrode was significantly reduced, validating the applicability of ac four-point impedance spectroscopy for electroceramics. DC current–voltage characteristics without any interference due to electrodes confirmed these ac measurements. Using ac four-point impedance spectroscopy, grain boundary contributions are isolated and the corresponding grain boundary thickness and resistivity are estimated.