Chapter 16 Information on Imperfections Matteo Leoni Abstract Line Profile Analysis is the common name given to those methods allowing microstructure information to be extracted from the breadth and shape of the peaks in a diffraction pattern. A fast analysis is always possible via traditional techniques such as the Scherrer formula, Williamson-Hall plot and Warren-Averbach method, but at the expenses of the physical meaning of the result. A more sound alternative is offered by the Whole Powder Pattern Modelling, allowing physical information to be extracted from diffraction data in a self- consistent way. 16.1 Introduction Nanostructured materials are still a hot topic in current research. An obvious choice for the analysis of the microstructure of such systems would be microscopy, as the sub-nm resolution can be easily achieved on last generation Transmission Electron Microscopes (TEMs) and Scanning Probe Microscopes (SPMs). However, obvious does not always mean better. SPMs mainly provide morphological information, whereas the TEM, albeit accessing morphology and microstructure information, is limited to the analysis of a few grains, a too small range to guarantee a good statistical significance of the measurements. A possible alternative is certainly offered by indirect methods such as powder diffraction. The microstructure information is contained, highly integrated, in a single powder diffraction pattern: already at the beginning of last century, in fact, it was observed a close relationship between e.g. the breadth of a diffraction peak and M. Leoni () Department of Materials Engineering and Industrial Technologies, University of Trento, via Mesiano 77, 38123 Trento, TN, Italy e-mail: Matteo.Leoni@unitn.it U. Kolb et al. (eds.), Uniting Electron Crystallography and Powder Diffraction, NATO Science for Peace and Security Series B: Physics and Biophysics, DOI 10.1007/978-94-007-5580-2 16, © Springer ScienceCBusiness Media Dordrecht 2012 173