Hi, just a question for about a doubt I have regarding the xrd analysis, maybe too trivial for experts....I have estimated the crystallite size in a thin films (my films have 100nm thickness), using rietveld refinement programs. I have always thought that in this way I estimated the size of the grains on the plane, on which I have the main average choerence. In fact I have found results of about 1500Angstroms. Is this correct? if the this value refers to the z direction, it should be wrong because higher than the film thickness...so how can I find the size of the crystallites along the direction normal to the sample? Thank you, Wunter.