It is well known that in the GIXRD technique, the x-ray beam is in incidence on the sample at a grazing angle that is higher than total internal reflection of the x-ray beam. What is the necessity of rotating the sample at some angular velocity?
Dear Sougata Koner ,
spinning of the sample is used to reduce preferred orientation artifacts in the XRD pattern. Due to the sample rotation you will have an angular average of crystallite orientations at least for that axis.
The spinning speed (angular velocity) has to be high enough to ensure sufficient angular average within the measurement frame(s).
Best regards
G.M.
Thank you, Prof. Gerhard Martens for the response.
But, what about the case of epitaxial thin films?
Epitaxial films exhibit strong preferred orientation because of the expitaxial property. That's why the spinning is essential; it scrambles the directions of the crystallites in that film; but, unfortunately, only in the plane of the film.
For epitaxial films it is worthwhile to check the preferred orientation; in that case one should not spin the sample; instead one has to do a pole figure measurement, which is performed by taking a series of XRD pattern while rotating the sample at small angular steps.
Please google for 'pole figure' and/or 'pole figure measurement' ...
Best regards
G.M.
- Badges
- Science topic
- Similar topics
- Entomology
- Resistance