Recent years have seen
to appear some new developments in adapting whole powder pattern profile
fitting techniques to severe cases of ill-crystallized materials, including
nanocrystallines.
More and more samples
show microstructure effects on line profile shape, width and position.
Reasons are obviously
the powder diffractometer resolution improvements at leading synchrotron
sources, and the increasing number of users.
When the minimal full
width at half maximum is as low as 0.01° (2q)
(synchrotron data), sample effects are no longer occulted by instrumental
effects.
Finer microstructure details
are revealed, needing adapted Rietveld software.
A review will be given of the new developments during the last five years, with a special emphasize on the meaning of some oversimplifications.