Hi everyone,
I synthesized Fe3O4 magnetic nanoparticles and characterized by XRD using CuKa λ=1.54˚A, 40 mV and 40 mA parameters in two different XRD diffractometer. But as you see in photos, I got two different results from the same sample and conditions. What is causing this differences?
best regards,
thank you
Looks like you sample was not mounted properly during one of the measurements.
K. Sreenivas
I used same sample at the both measurement. I did not prepared two sample for the two measurement
Please check the 2 theta step in both two different XRD diffractometer.
May be one of them has 2 theta higher than the other.
or check the type of crystallizes peak that appears in the second photo. May it helps us to realize what happened precisely.
Dear Kübra,
as K. Sreenivas wrote above something is wrong in your set up.
Your sample might not be properly mounted at the right height relative to the centre axis of your x-ray optics. Your detector of the 1st device preferably sees background from elsewhere. Please play around with that height parameter.
thank you all
the 2 theta step was always 0,05
I will prepared properly my samples next time.
I appreciate to your advices.
Dear Kübra, perhaps one of the diffractometers is not adequately calibrated. The threshold and the window of the amplitude of the fotomultiplier signals are not selected in the rigth way, you might be registering fundamentally radiation from the bremstralung of the X-ray tube but not CuK-alfa. The answers of the other colleagues are also valid.
Run a standard sample, such as corundum, silica or similar that is well characterised and compare the two. This is a basic check for the alignment of the diffractometers. Most diffractometers should have a standard material for calibration checks. Then if these results are similar you can start to think about sample problems.
Many factors can make this difference.
1- two different equipment .... Check: beam alignment, vertical beam size,
2- verify: the height of the sample in relation to the sample holder
3 - verify : if the compaction of the sample generated preferential orientations.
Sorry Kübra, but I read again your question and I now perceived an important detail: you are dealing with Fe3O4 nanoparticles. In these case, if you discard the equipment discalibration and misalignment, you may think about the time effects on the sample. Perhaps a slow change in crystalinity could be realized between XRD runs. Please, run DRX on the same equipment and the same sample just as sinthesyzed and with time delays.
Interesting result Kübra. If nothing wrong with the instrument, procedure, set up, sample preparation, preferred orientation issue then it could be a rapid change from the amorphous state to crystalline state.
If possible do one more synthesis and do the same procedure to rule out the above problems.
Also, sometimes DSC is helpful to understand the amorphous to crystalline state transformation in which you can see clear rubbery phase exothermic transition.
Good luck with your research Kübra.
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