Grain boundary structure and I-V characteristics were investigated for Nb-doped SrTiO3 bicrystals having low-angle tilt boundaries with misorientation angles of 2º and 4º with respect to [001]. The bicrystals were fabricated by using the hot-joining technique at 1400C for 10h under a pressure of 0.4MPa. High-resolution transmission electron

microscopy revealed that the joined boundaries were free from any secondary phases, such as amorphous phases; even at the atomic scale. The structures of the 2 boundaries were composed of edge-type dislocations whose Burgers vector was [010]. The density of boundary dislocations differed between the 2 boundaries. They existed at an interval of 10nm in the 2º-boundary and 5.2nm in the 4º-boundary. On the other hand, it was found that non-linearity in the I-V relationship across the boundary increased with increasing misorientation angle. This clearly indicated that the potential barrier height was closely related to the density of boundary dislocations in the case of low-angle type boundaries.

Current-Voltage Characteristics across Small Angle Symmetric Tilt Boundaries in Nb-Doped SrTiO3 Bicrystals. T.Yamamoto, F.Oba, Y.Ikuhara, T.Sakuma: Materials Transactions, 2002, 43[7], 1537-41