Dear Angel,
I think you should pay attention to articles by Paolo Scardi and Matteo
Leoni.
They have developed a very powerful technique called WPPM (Whole Powder
Pattern Modelling) which is designed for microstructural analysis from XRD
data.
I suggest that you should check these papers:
1. P. Scardi, M. Leoni. Acta Cryst A58 (2002) 190-200.
2. M. D'Incau, M. Leoni, P. Scardi. J. Mater. Res. 22 (2007) 1744-1753
3. J. Martinez-Garcia, M. Leoni, P. Scardi. Acta Cryst A65 (2009) 109-119
and references therein.
A short and simple answer will be that XRD profiles taken for ball-milled
materials are much more distorted by dislocations than by vacancies. One of
the simple reasons is that dislocation-induced strain field decays as 1/R
and vacancies-induced strain field decays as 1/R^2 where R is distance from
diclocation core or vacansy center.
With best regards,
Eduard.
----- Original Message -----
From: "Angel L. Ortiz" <alor...@unex.es>
To: <rietveld_l@ill.fr>
Sent: Wednesday, September 09, 2009 11:32 AM
Subject: defect measurement
Dear colleagues:
I am writing to formulate a question on the evaluation of defects by XRD.
This is the following:
I have a ball-milled material, and I would like to define the type of
defects induced by the ball milling. In particular, I would like to
elucidate whether the ball milling has induced vacancies, or dislocations.
Could any of you help in this issue, and indicate how this can be done and
how one can know the type of defect from the XRD pattern?
Thanks a lot,
Angel
