QUANTIFICATION OF GRAIN-BOUNDARY SEGREGATION IN TIO2 BY STEM

A complete characterization of interfacial segregation involves knowing both the concentration of a solute or impurity and its spatial distribution, often at the subnamometer scale. However, in many materials problems the segregation per unit area of interface is a useful quantity. An example is the problem of space-charge segregation at interfaces where the aliovalent solute density per unit area of interface is equivalent to the charge-density per unit area. We have developed a new analytical method for measuring the solute segregation density at interfaces, here applied to the quantification of space-charge segregation at grain boundaries in TiO2. Application of space-charge theory, in essence the application of Gauss' law and Poisson's equation, allows the electrostatic potential to be deconvolved from segregation data.