A method for rigid body expansion measurement in the presence of secondary grain boundary dislocations applied to a SrTiO3 grain boundary

In this paper we present a method for measurement of rigid body expansion at near-CSL grain boundaries, which treats secondary grain boundary dislocations explicitly. This method makes use of high resolution electron microscopy images. As a case study, a strontium titanate (SrTiO3) near- Σ 3 ( 1 1 2 ) [ 1 ¯ 1 0 ] grain boundary has been characterized. The Frank circuit method is used to characterize the Burgers vector of the dislocation as b = (a0/6)[1 1 2] (where a0 = 3.905 Å is the SrTiO3 lattice parameter). Using the proposed method for expansion measurement, the rigid body expansion at the boundary is measured to be (0.07×0.05) Å. This result is compared to theoretically predicted grain boundary expansion and is found to be in better agreement with one of the two model structures proposed in the literature.