ABSTRACT
Abstract. Fresnel fringes are found at both film-containing and film-free grain boundaries in Y-doped alumina. For the film-containing boundary the inferred film thickness was significantly smaller than that measured by HRTEM. It is suspected that interface diffuseness or a compositional gradient caused this effect. In the film-free case, the appearance of Fresnel fringes was attributed to a local reduction of the inner potential at the grain boundary due to a dopant-induced grain boundary expansion, in line with a recent theoretical study of the effect of dopants on boundary structure in alumina. It is concluded that the strong dopant segregation to alumina grain boundaries can lead to confusing results in Fresnel fringe analysis.
