I would like to know the about the laue oscillations when we zoom an XRD pattern. What do these laue oscillations indicate when they are symmetrical and asymmetrical? What do they indicate is they are not well-defined or are rough (or are not present at all)? Is there any good article or book, that can tell about the analysis of the laue oscillations?
Please share your XRD data with the "oscillations". What epi thickness?
I also suggest recording the substrate XRD signal prior to epi deposition and post, to contrast.
Reciprocal Space Oscillations: Do you mean like this that we found with (004)s reflection for the LSCO/LSAO superconducting system using Panalytical HRXRD? I was under the impression that these were pendellosung fringes due to the 50nm thin epi of LSCO.
Real Space Oscillations: We also found "oscillations" in the (113)- & (224)- reflection topographs, integrated through the Bragg range, for the NIST 2000 Standard Reference Material using the Bruker HRXRD system. These oscillations seem to be present with and without film. On both sides of the sample front and back.
Some references for "Laue Oscillations" would be appreciated :-)
https://www.flickr.com/photos/85210325@N04/8036412739/in/photostream/
https://www.researchgate.net/post/What_could_the_origin_of_striations_be_on_a_113-XRD_reflection_integrated_topograph_for_the_NIST_2000_SRM_standard_reference_material
Interesting pattern. I believe that some of the peaks can be indexed to tetragonal Sr2RuO4 [Crystal system: Tetragonal Crystal system: Tetragonal Space group: I4/mmm Space group number: 139 a (Å): 3.8732 b (Å): 3.8732 c (Å): 12.7450 Alpha (°): 90.0000 Beta (°): 90.0000 Gamma (°): 90.0000 ], but as Ravi said, please index all the patterns including the substrate peaks.
The strong peak at 2theta = 42.65 has some pendellosung oscillations(or Laue oscillations) on it, although these oscillations are not so clear. Don't know if this is an instrument/measurements issue or sample issue. I would suggest that to do scan near 2T = 42.65 to include the film and substrate peak, increase count time to reduce the statistics. If u see, clear Laue oscillations, then those can be modeled to extract out the film thickness (in the number of unit cells).
The presence of clear oscillation fringes indicates that film - interface and film-air surfaces are smooth, so specular scattering at these interfaces can give rise to constructive interference fringes. The absence of fringes can imply that the surfaces are rough.The lattice mismatch between your film and substrate is M = [(3.873-3.868)/3.868] ~ 0.1%, very very low, implying that under proper conditions (anatomically stepped substrate, precise growth parameters), you should get
The absence of fringes can imply that the surfaces are rough.The lattice mismatch between your film and substrate is M = [(3.873-3.868)/3.868] ~ 0.1%, very very low, implying that under proper conditions i.e. anatomically stepped substrate, precise growth parameters, you should get very smooth films. Smooth films would give very good pendellosung fringes, while minimal strain implying reduced point defects. and reduced threading dislocations density.
However, since these films are grown by Oxide MBE (right??) so control of the Sr, ru and O fluxes are critical. Since Sr-Ru-O can form various compounds (eg SrRuO3, Sr2RuO4, Sr3Ru2O7) if the cations ratio is nor proper. So possibly I would think that u have a minority impurity phase possibly at one of the interfaces, reducing the clarity of the oscillations. A better understanding of the theta-2theta scan will help u understand what are the structural properties of these films. You should also do GIXRD scans, so u can get signal from any impurity peaks that are not epitaxially aligned to the substrate. If GIXRD doesn't give any peak, then there are no secondary phases, but if it gives some peaks, then there are some trace impurities in your samples.
Meanwhile, if u really want to quantify the sample roughness, i would suggest that you do XRR and analysis the fitting using software such as genX
Hope this helps
" using software such as genX", got link?
https://www.researchgate.net/post/What_depths_can_one_typically_probe_with_XRR_X-ray_Reflectivity_Reflectometery
https://www.researchgate.net/post/How_can_measure_thin_film_thickness_by_XRD2/1
https://www.researchgate.net/post/what_cause_satellite_peaks_in_XRD_measurement
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