화학공학소재연구정보센터
Journal of the American Ceramic Society, Vol.86, No.11, 1933-1939, 2003
Surface energy anisotropy of SrTiO3 at 1400 degrees C in air
Geometric and crystallographic measurements of grain-boundary thermal grooves and surface faceting behavior as a function of orientation have been used to determine the surface energy anisotropy of SrTiO3 at 1400degreesC in air. Under these conditions, thermal grooves are formed by surface diffusion. The surface energy anisotropy was determined using the capillarity vector reconstruction method under the assumption that Herring's local equilibrium condition holds at the groove root. The results indicate that the (100) surface has the minimum energy. For surfaces inclined between 0degrees and 30degrees from (100), the energy increases with the inclination angle. Orientations inclined by more than 30degrees from (100) are all about 10% higher in energy and, within experimental uncertainty, energetically equivalent. A procedure for estimating the uncertainties in the reconstructed energies is also introduced. Taken together, the orientation dependence of the surface-facet formation and the measured energy anisotropy lead to the conclusion that the equilibrium crystal shape is dominated by {100}, but also includes {110} and {111} facets. Complex planes within about 15degrees of {100} and 5degrees of {110} are also part of the equilibrium shape.