Comparing with PDF card. The intensity of main peak is lower than the other secondary peaks. All peaks not only shift rightward but also have shoulders. What do these mean?
There are four observations. Let me discuss them and related conclusions one by one.
1. The intensity-ratios don't match, however their positions are more or less same. It indicates, there are some non-uniform crystal-growth dynamics and preferred orientations. The (200) peak is extremely great, means the growth is predominant in this direction.
2. If you keep (200) peak aside, even then the intensity-ratio of other peaks also don't match. I think, the asymmetric and anisotropic growth dynamics need further attention and other spectroscopic explorations.
3. All peaks have a small shoulder at the left side. It simply indicates, you have two phases in the material. The dominant and major component gives the main peaks. The other small component gives the shoulders. (Here I'm assuming that, the shoulders are your sample-properties and the X-ray source you are using is by default kβ and kα2 corrected. If your system itself does not accompany strictly monochromatic radiation, then such double-peaks will commence for any sample under use. I hope, that is not the case.)
4. The peaks are right-shifted. It indicates, a smaller interplanar spacing. From Bragg's law, you can say if the theta positions increase, d-positions decrease. And a smaller interplanar spacing leads to a smaller unit cell. Anyway, the right-shifts might be different for different Bragg peaks. In that case, you may find that, the interplanar spacings between different (hkl) planes have been influenced by the preferred growth-directions differently. (Again here I assumed, the shifts are not due to some instrumental error and represents material characteristics.)
Hi Zhou Xiangji ,
The high intensity of the 200 peak indicates, your sample has preferred orientation (texture) in the 200 direction.
The shoulder of the peaks may be due to improper filtering of the incident X-ray beam, I mean X-rays of two defferent wave-lengths may be present in the incident beam.
For details about the shoulder, you can check the Answers of the following :
https://www.researchgate.net/post/The_shoulder_on_the_XRD_peak_What_could_it_be
There are four observations. Let me discuss them and related conclusions one by one.
1. The intensity-ratios don't match, however their positions are more or less same. It indicates, there are some non-uniform crystal-growth dynamics and preferred orientations. The (200) peak is extremely great, means the growth is predominant in this direction.
2. If you keep (200) peak aside, even then the intensity-ratio of other peaks also don't match. I think, the asymmetric and anisotropic growth dynamics need further attention and other spectroscopic explorations.
3. All peaks have a small shoulder at the left side. It simply indicates, you have two phases in the material. The dominant and major component gives the main peaks. The other small component gives the shoulders. (Here I'm assuming that, the shoulders are your sample-properties and the X-ray source you are using is by default kβ and kα2 corrected. If your system itself does not accompany strictly monochromatic radiation, then such double-peaks will commence for any sample under use. I hope, that is not the case.)
4. The peaks are right-shifted. It indicates, a smaller interplanar spacing. From Bragg's law, you can say if the theta positions increase, d-positions decrease. And a smaller interplanar spacing leads to a smaller unit cell. Anyway, the right-shifts might be different for different Bragg peaks. In that case, you may find that, the interplanar spacings between different (hkl) planes have been influenced by the preferred growth-directions differently. (Again here I assumed, the shifts are not due to some instrumental error and represents material characteristics.)
Dear Zhou Xiangji ,
I gree with Souvik Bhattacharjee, he has mentioned the most possibilities that could interpret your results.
Regards
Thank you very much. You guys are so kind and smart. I'll do further characterization on my sample based on your suggestions. Souvik Bhattacharjee Rajan Biswas Abdu Saeed
Your phase identification is either incorrect or incomplete.
The small preaks to the left of the main peaks look like matches to the pdf and their relative intensities may be correct.
The small peaks to the left do not look like K-beta (too close to the big peaks), and the pattern does not look like K-alpha2, either.
If your sample was sintered, you may repeat the sintering process (for a small portion of the sample) but for a longer time interval, and then record its XRD pattern. That might help removing any second phase or any irregularities in your sample.
- Unexpected high intensity of (200) plane surely indicates preferred orientation, which can be taken into account for crystal structure analysis through Rietveld refinement.
- Position of peaks at left side in the (i guess (220) and (311)) pattern match well with the pdf card. There can be possibility of sample existing in two phases or showing any phase transition. Also, presence of impurity cannot be neglected. However, the right side peaks are not of Kalpha2, since these should be approximately of half intensity than the Kalpha1 line.
Megha Jain When you said "the right side peaks are not of Kbeta, since these should be approximately of half intensity than the Kalpha lines." I think you mean the right side peaks are not of Kalpha2, since these should be approximately of half intensity than the Kalpha1 lines. Or, possibly the left side peaks are not of Kbeta, since these should be approximately of one fifth intensity of the Kalpha lines.
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