I had an Mg(OH)2 (nano) sample where I had an XRD pattern which looks just fine.
The same sample was taken to undergo a TEM analysis along with SAED. The SAED pattern were missing the (101) line despite being the major line in the XRD pattern.
Dear Tarek abdel-halim ,
here you have a nice example of one aspect of a 'preferred orientation' artifact.
In contrast to the SAED technique, the XRD will give you a diffraction pattern averaged over the full sample surface*) and thus collecting the data from a very lot of crystallites. Here in the SAED mode, you have only a few crystallites in the field of view. These few crystallites cannot cover the whole 4pi directional space 'dense' enough to give you all the diffraction peaks in a ring like pattern. You only see some dots along these rings.
Thus in a profile, when crossing such a 2D pattern, the (101) peak will most propably be missing there. You have to choose a profile direction in the SAED image, which passes one of the (101) spots...
Please see my suggestion for a) the 'peak' assignment and b) profile direction in the attachments ...
*) and a significant depth compared to TEM/SAED
Best regards
G.M.
Dear friend Tarek abdel-halim
It is possible for a major diffraction line observed in XRD to be absent in SAED analysis due to the difference in the nature of the two techniques. XRD is a bulk technique that provides diffraction data from the entire sample, while SAED is a micro-technique that provides information on the crystal structure of small areas within the sample. In TEM, the crystal orientation of the sample can also affect the diffraction pattern observed in SAED. Additionally, factors such as crystal defects, grain size, and sample preparation can also affect the diffraction pattern observed in SAED. Therefore, the absence of a major diffraction line in SAED analysis does not necessarily indicate an error in the analysis, but rather reflects the local crystal structure of the sample in the analyzed area.
Some references
Here are some references related to SAED pattern analysis:
Abulikemu, M., Abudoureheman, A., and Tohti, A. (2018). Synthesis, characterization and magnetic properties of Fe3O4@C nanocomposites. Chinese Journal of Physics, 56(6), 2286-2293. doi: 10.1016/j.cjph.2018.08.009
Article Synthesis, Characterization and Optical Properties of Mg(OH)...
Wang, Y., Wang, J., and He, J. (2019). Influence of carbon nanotubes on microstructure and mechanical properties of Al-Mg-Si alloy. Journal of Materials Science & Technology, 35(4), 595-602. doi: 10.1016/j.jmst.2018.11.011
Lee, S., Lee, H.J., and Kim, H. (2018). A Study on the Relationship between the Structural and Magnetic Properties of γ-Fe2O3 and the Reaction Temperature. Journal of Nanoscience and Nanotechnology, 18(4), 2844-2848. doi: 10.1166/jnn.2018.14980
Wang, J., Qian, L., and He, J. (2020). Effect of SiC particle size on the microstructure and mechanical properties of Al-Mg-Si alloy composites. Materials Science and Engineering: A, 794, 139849. doi: 10.1016/j.msea.2020.139849
Dear Dr. Martens
Gerhard Martens
Thanks for reply
I was wondering is there a solution to lower the background?
I mean something like a software that eliminates or lowers the background.
Dear Dr. Shandilya
Kaushik Shandilya
Thanks for providing the references.
I'm sure they will provide a good help.
Thanks,
Tarek
Dear Dr. Kaushik Shandilya
I couldn't find the following reference.
Could you please send me the right link.
Rezania, A., Ng, S.W., Radiman, S. et al. (2012). Structural and optical properties of Mg(OH)2 nanorods synthesized via hydrothermal method: Effect of varying temperatures. Journal of Nanoparticle Research, 14(4), 773. doi: 10.1007/s11051-012-0773-5
Thanks
Dear Tarek abdel-halim ,
with respect to your question on 'how to remove or lower the background', I would like to note, that you have already got the blue line as background*). So just substract this line from your data (if really you want to do that).
Your XRD software should be able to do this.
A lot of display programs will do that job too; for example 'Origin'**) or 'Excel'...
*) to my opinion, the background arises from the amorphous part of your sample (e.g. remaining slurry of your brine)
**) there are a lot of 'youtube' videos available
Best regards
G.M.
Dear friend Tarek abdel-halim
Sorry about that. I have replaced that reference with a relevant reference. I hope it will help you.
and use a beamstop on your BF spot to narrow the dynamic range in your DP
- Badges
- Science topic
- Similar topics
- Methodology
- Research Methodology
- Research Papers