[sdpd] Re: random orientation in flat plates nanocrystallites

[Armel Le Bail <armel...@fluo.univ-lemans.fr>]

If I understand well your 30*200*200nm (as seen by electron
microscopy ?) nanocrystallites powder diffraction data are well
fitted (Rietveld ?) by an isotropic grain size model ? Well, we
need to know the resolution of your instrument (U, V, W values
of your fit) because a bad resolution could give FWHM almost
the same for 200 or 30nm crystallites. We need to know the
crystal system. It is unusual to have platelets with a cubic
symmetry, but if this is the case, then you may not see any
anisotropic size broadening. If your compound is orthorhombic,
you should see the h00 much broader than the 0k0 and 00l. But
if there is a big preferred orientation effect, you will not see the
0k0 and 00l...

Tell us more.

Best,


Armel Le Bail - Universite du Maine, Laboratoire des Fluorures,
CNRS ESA 6010, Av. O. Messiaen, 72085 Le Mans Cedex 9, France
http://www.cristal.org/