Investigation of Improved Reliability in BaTiO3-Based Ceramics via Two-Step Sintering by Impedance Spectroscopy and Schottky Barrier Model

The ceramics prepared by conventional sintering (CS) method and two-step sintering (TSS) method are investigated in the temperature range of 490-570 degrees C through impedance spectroscopy, which is correlated with the improved reliability of TSS specimen. There is an improvement in the resistances (R-g and R-gb) of TSS specimen mainly due to the reduced grain size. And according to the grain boundary double Schottky barrier model, not merely the smaller potential barrier height (?(gb)) but also the larger depletion layer thickness ((gb)) for TSS specimen indicate that the effective concentration of charged acceptor dopants and hence oxygen vacancy concentration in TSS specimen are much lower than these in CS specimen. These facts can account for the improved reliability in BaTiO3-based ceramics via two-step sintering.