XRD peaks in the Ni doped Zn Ferrites are observed to shift slightly with the variation of both contents. Why does it happen? And what kind of message may we get from it?
Dear @Rakibul hassan
According to my experience and from literature, XRD peaks shifts from the original position due to the increased/decreased height of the specimen in the specimen holder.
Dear Rakibul Hassan
Hoping you are fine.
As Bala Bala Narasimha Guniputi suggest, it could be due to position in the specimen holder, nevertheless, it could be also related with changes in the crystal structure of your sample. Please, see how large is the shift of your sample with respect to pattern material.
There are a lot of examples in the literature that suggest that when diffraction peaks shift to another angles it could be attributed to:
1) Changes in the crystal size (because shift and change in the intensity according to Scherrer's equation)
2) Changes in the crystal structures because substitution or simply by changes of the percentage of each component during the synthesis.
* Do you perform a refinement of your XRD pattern? if no, you could use EVA or another program to do this.
*Did you calculate the percentage cristallinity of your sample after modification, if no, please calculate this (if cristallinity did not change significantly, changes in the shift could be attributed to position in the specimen holder)
If you have a doubt, please let me known.
With kind regards,
Julián Sánchez.
Variations in the height of the specimen in its holder, whether increasing or decreasing, cause XRD peaks to change from their original location.
Important and useful pathways are connected to the XRD Curve:
Scherrer’s equation:
Particle Size = (0.9 x λ)/ (d cosθ)
λ = 1.54060 Å (in the case of CuKa1) so, 0.9 x λ = 1.38654
Θ = 2θ/2 (in the example = 20/2)
d = the full width at half maximum intensity of the peak (in Rad) – you can calculate it using Origin software.
To convert from angle to rad
Rad = (22 x angle) / (7 x 180) = angle x 0.01746
Example: if d = 0.5 angle (θ)
= (22 x 0.5)/ (7x 180) = 0.00873 rad
Dear Rakibul Hassan
When the contents materials or the temperature are changed, the XRD graph has a shifted peak. Peaks on the plane shifted, such as from one degree to another, higher intensity to lower intensity.
Dear Rakibul Hassan
The changes in the peaks may be external (caused while making measurements etc) or internal (structural etc).
If the changes are structural, then that indicates changes in structural parameters.
Basically, the XRD peaks arise due to the diffraction from the various atomic planes. Therefore, changes in atomic positions, interplanar spacing, lattice parameter, compound density results into change in position, intensity and FWHM of peaks.
These changes can be calculated using Bragg’s law or Scherrer’s equations or Rietveld refinement.
I hope this paper might be helpful:
Journal of Electron Spectroscopy and Related Phenomena 235 (2019) 29–39, https://doi.org/10.1016/j.elspec.2019.06.004
Dear Rakibul Hassan
XRD peaks shift according to Bragg's formula if the interplanar spacing changes between successive Bragg planes. And this happens when the lattice parameters of the unit cell get modified.
This can happen due to substitutional doping of larger or smaller atoms, interstitial doping, vacancy-defects, synthetic protocol, development of internal strain, external stress, disorder, size-variation etc. In your case, doping seems to be the contributing factor.
The shifting of peaks is related to lattice parameter of the samples. With doping, if the lattice parameter increases, peaks should shift to lower Bragg's angle and the reverse if the lattice parameter increases. However for complex symmetry structures, where a, b, c are unequal, there the variation may not follow trend. Refer to some papers.Article Structural and proton conductivity study of BaZr1-xRExO3-δ(R...
Dear Rakibul Hassan,
The shifting of the XRD peaks may depend on-
1. increase or decrease of the lattice parameter which is attributed to doping or impurities. Generally, peaks shift to lower Bragg's angle if the lattice parameter increase and vice versa.
2. the changes of interplanar spacing between successive Bragg planes.
There are some more reasons for the changing of the intensity peaks depending upon the materials, temperature, etc.
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