Nd. Browning et al., The influence of atomic structure on the formation of electrical barriers at grain boundaries in SrTiO3, APPL PHYS L, 74(18), 1999, pp. 2638-2640
An experimental atomic resolution analysis of an undoped Sigma 5 36 degrees
[001] tilt grain boundary in SrTiO3 shows that the structure contains inco
mplete oxygen octahedra. These incomplete octahedra act as effective oxygen
vacancies and lead to a fixed, positive boundary charge. Annealing the bou
ndary in the presence of MnO2 does not change the atomic structure of the b
oundary plane, and results in a high concentration of Mn3+ (acceptor) enric
hment at the specific Ti4+ locations in closest proximity to the effective
oxygen vacancies. This result can be explained in terms of standard charge
compensation models and indicates that the formation of electrical barriers
at oxide grain boundaries may be influenced by the atomic structure of the
boundary plane. (C) 1999 American Institute of Physics. [S0003-6951(99)006
18-X].