I am analyzing XRD pattern of PrBaMnO. my question is can we compare the peaks that have some shifts from original XRD JCPDS cards? Actually my peaks not matching with any card?
Hi Shoaib Ajmal,
What kind of a peak mismatch is it exactly? If there is a consistent 'constant' shift of all the peaks (to the left or right) compared with the reference, then it's simply a 'zero shift' (meaning your 0 point on the x-axis is misplaced in the process of digitizing your data) and this you can simply manually zero shift (i.e. add or subtract some value from the entire 2theta column) by the right constant value to arrive at a match with the standard.
Otherwise, it could mean that your sample is not pure and there are foreign ions present in your structure (e.g. your sample is doped with something else) or it could even be that you have synthesized a different phase.
Only more specific details can help us understand the problem.
Best regards,
Jamal
Are you using the same anode as the reference (typically copper) or another anode. It could also be different phase of the material, or even possibly wrong material synthesized.
Riettveled refinement can answer your questions. Have a look at Fullprof or JANA software and manuals.
JCPDS - new ICDD card deal with powder plain samples.
No monocrystal - no - mosaic.
If the shape of your sample is not slab, you'll get shift.
If your powder slab has preferential grain orientation duering rental, press or drawing you'll get shift too.
Use inner standart: mix of your grains and grain of standart powder.
No monocrystal - no - mosaic, no texture with preferential grain orientation duering rental, press or drawing you'll get shift too
Sorry Michael E. Boiko, but I'm not sure I understand your incomplete sentences.
Powder diffraction does indeed require polycrystalline samples with very large number of crystallites illuminated by the x-ray beam. But I don't know what "No monocrystal - no - mosaic" means.
"If the shape of your sample is not slab, you'll get shift."
This doesn't sound correct. But perhaps he means if the sample is not flat, it will cause a shift, which can be true sometimes. The most common aberration in powder diffraction is due to radial sample displacement (normal to the sample surface). This will cause an angle-dependent shift in peak positions, which is maximum at low scattering angles and minimum for high scattering angles. So, if a sample is not flat in a way that displaces all of the part the x-ray beam sees from the reference position, peaks will be shifted.
However, if a sample is just not flat (if round or tilted or rough surface), the portions above ideal and below ideal will combine to broaden the peaks - not shift them.
It depends on where the illuminated region is relative to the proper reference surface.
"If your powder slab has preferential grain orientation duering rental, press or drawing you'll get shift too."
Not sure what "rental" means in this context, but this is definitely false. preferred grain orientation or texture will alter relative peak intensities, not shift their angles.
To get a sustainable solution to your problem, please refer to the preprint article given at link DOI: 10.13140/RG.2.2.27720.65287/3 or at link https://www.researchgate.net/publication/352830671.
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