Hello,
I have deposited some ZrN coatings with different amounts of Cu (0-30 at.%) by reactive magnetron sputtering. In the XRD patterns, I can see the shift to the higher diffraction 2-thetas but just for some of the peaks. I do not see any shift for (111) and (200), but at the same time, (220) and (311) are shifting towards the higher angles with increasing Cu content. Does anybody have any idea about the reason?
Thanks in advance.
Internal Stresses are generally the main reason of a peak shift. It is possible that some particular phases are the main cause of the stresses then others. The process parameters, the target properties, the coating methodology etc. are the factors which can lead to stresses in some phase then others.
Generally, the XRD shift for all the peak is either the left or right side. In this case, some peaks have been shifted right and some peaks no shift, which seems to be contracting peaks shift patterns.
In my opinion, you should enlarge the 2-theta of the no shift peaks and check whether there may be very small shift, then we see the cause.
Hello,
It can be seen in the figure that with increasing Cu content there is not only shifts of some lines, but also a significant change in the intensity ratio, especially for lines (111) and (200). Therefore, I do not think that it will be the effect of microstress, but rather a reduction in symmetry, or a change in the space group due to the incorporation of Cu into the ZrN structure. Another possibility is a phase transition or addition of another Zr nitride (Zr3N4 etc.) It would be good to do some modeling using the Rietveld method.
Muhammad Naveed
Thanks for the answer. But here ZrN is just one phase and as far as I know (maybe I am wrong), peak shift must happen for all the diffraction peaks of the same phase. In this case, just two of the peaks shifted and the others almost fixed. It is likely that Zr atoms were substituted by Cu atoms but this substitution has shifted just the position of (311) and (220).
Dattatray Gadkari
Thanks for the answer. I think you are right, and if I zoom in, I would see a very small shift. I will try it. But now the question is: is it usual to have very small shifts for some peaks and larger shifts for the rest? The reason can be the fact that Zr atmos have been substituted in some planes more than the other planes?
Dalibor Matýsek
Thanks a lot for the answer. Yes, it is obvious that the coatings are textured especially for the lower copper contents. When the copper content is 25% or 29% the intensity does not change. The formation of another zirconium nitride phase is less likely as the existence of ZrN is approved also by TEM. I do not know the reason why some of the lines shift more and some of them less. Maybe the tendency of Cu atoms to some specific planes?
If the symmetry changes from cubic to another (ie. is degraded), it is easy to imagine that one of the lattice parameters is affected by the substitution more than the others. Then the described situation easily occurs.
Sahand Behrangi
Hi!
Your interpretation seems more logical. Thus phase transition has been occurred, may be related to the substitution of the atoms.
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