An XRD pattern with an intense peak of 311 in a standard JCPD card of Cobalt oxide remains fine but after the dopping of palladium oxide the peak shifted more towards left and why not right? I read somewhere that peak shifts are due to expansion or contractions but they they occur due to dopping?
Dear Rehan Qureshi ,
this topic often pops up here on RG. You may also 'google'...
So please see for example the answers of:
https://www.researchgate.net/post/Does-the-doping-process-lead-to-XRD-peaks-shifting-in-2th-direction-or-change-in-the-peaks-intensity
https://www.researchgate.net/post/Is-shifting-of-xrd-peaks-obvious-during-the-doping-What-extent-of-XRD-peak-shiftingeg-1-degree-is-acceptable
https://chemistry.stackexchange.com/questions/6138/effect-of-dopant-size-on-xrd-peak-shift
In short, when an atom of the host matrix is replaced by a dopand atom having lower diameter the lattice constant(s) will decrease a bit und thus (according to the Bragg law) the theta angle is increased a bit (or at least broadened a bit to the right side).
For the case of an atom of the host matrix being replaced by a dopand atom having larger diameter the lattice constant(s) will increase a bit. Thus one will have a decrease of the Bragg angle theta (or at least a peak broadening to the left side).
Best regards
G.M.
The first reason, the unit cell parameters change of your sample. The second reason, the sample is not well placed during XRD measurement.
Lower angle = expansion of the lattice, higher angle = contraction. Both of which can be induced by substituting with a larger or smaller atom (by doping). Position error causes a different kind of apparent angle shift and can be identified and corrected for if you have enough peaks
The left/right shift in XRD spectra occurs due to the change in lattice parameters, kindly refer to the XRD section of the following articles: hope this helps:
Article Effect of Cu-N co-doping on the dielectric properties of ZnO...
Article Effect on the dielectric properties due to In–N co-doping in...
Article Effect of synthesis methods on dielectric performance of ZnO...
Hello,
According to Bragg law, the shift to the right is related to the contraction of the crystal lattice (decrease in crystal parameter values).
Shift to the left, ie. an expansion of the crystal lattice.
This contraction or expansion of the crystal lattice is generally linked to different parameters:
- The temperature (heating gives an expansion - shift to the left).
- The size of the added atom (atomic radius): example: the addition of a doping atom contains a large size gives an expansion of the crystal lattice).
- Mechanical deformation.
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