Microstructure from diffraction: progress in line profile analysis

Line profile analysis is one of the fields of diffraction that received a huge boost in the last decade or so. This has not been the mere effect of the availability of faster computers. The limits and risks of the traditional line profile analysis methods (Scherrer formula, Williamson-Hall plot, Warren-Averbach method and their modification) for a quantitative analysis of the microstructure have been identified and critically discussed. The need for an accurate information on the nanoscale, where each particle matters, has lead to an elegant mathematical inclusion of a distribution of shape, size and microstrain in the most complete Fourier approach of line profile analysis. The main revolution, however, has been in the way data is handled. We moved from a deconvolutive single peak analysis to the analysis of multiple peaks with analytical profile functions (Multiple Whole Profile method) and then to an ab initio convolutive full pattern approach (Whole Powder Pattern Modelling) that can be considered the microstructural complement of the Rietveld method. An overview of those changes and their impact on the accuracy of the quantitative microstructural result, as well as some caveats for potential users will be presented and discussed.