I'm trying to refine the magnetic structure of BaFe12O19, but I don't know the process of the refine step.
Hi Li,
First, you have to match your neutron diffraction data with a Ba ferrite-like structure. Some softwares that do that are Crystallographic or Match, look also for Italian Maud package. Then, if you don't have spurious phases like barium carbonates you can proceed to refine your structure. The crystallographic information file (cif file) will also give you information about cell parameters, space crystal group and atomic positions. Useful guidelines from MIT are available on the internet. Check ppt or PDF for basics of Rietveld refinement and procedures. For refinement you can employ Fullprof or Maud. Regards.
Hi, I just outline the process how I would start a refinement of the magnetic structure - I will point you to: https://conference.sns.gov/event/22/page/5 where you can find the lecture notes for magnetic structure refinement.
1. Get the cif structure file from the ICSD and use cif to pcr to get the structural input file.
2. Run a refinement on the data in the paramagnetic regime to get the scale factor and peak shape.
3. Use SaraH (http://fermat.chem.ucl.ac.uk/spaces/willsgroup/)
3a. do a symmetry analysis
3b. set up a refinement pcr
4. use the refinement pcr as second phase, keeping scale factor and shape parameters. Thus you only refine the magnetic moment amplitude in your magnetic data set.
This should get you started, since the magnetic structure is k=0 you might have problems to determine the magnetic moment size correctly.
At first, start the process by using SARAH Apps to make the magnetic Phase. But, before you go further with this, make sure the structure refinement is already done well. Let's assume you already done. The SARAH Apps can help you to make a .mat file. There are two Apps, (1) SARAH Irrep Analysis, in which you make a .mat file. Just read the instruction on the Apps tab. everything there. (2) SARAH Refine, this Apps allowed you to extract all the magnetic information by choosing any appropriate Basis vector of the Irreducible representation. Namely, in this Apps, you will get a .PCR file that contain the magnetic phase it self.
having done, copy paste all the information in the .PCR (magnetic phase) into the structural .PCR (nuclear Phase) that you refined before. Copy paste also the same profile parameter for both phase. Next, dont forget to change the mix coef as much as the Basis vector of the Irreducible representation you have. Change the Nph = 1 into =2, save then start the refinement.
It is so complicated to refine the magnetic structure. ..............
Hello..... Mr. Putu Eka Dharma Putra
Please can you suggest making .mat file for SARAH?
Guru Dutt Gupt There is a software called SARAH Irrep Analysis, all the instruction to make the .mat file is already there. Just open the apps, there is a tab, right beside it, that is the step by step instruction.
Thank you for your reply Putu Eka Dharma Putra, but still, I did not get the method to create .mat file. Right only suggest the procedure to upload that file.
Guru Dutt Gupt Just open the Apps, go to help video menu on the top, there are some tutorial for you also. or go to here https://www.youtube.com/playlist?list=PL5d_J0_DlgTfam9WbJeunhwGcHC5u5yvj
everything is there
Dear sir, You can use this video for a better understanding of the refinement process.
(Full Tutorial on Rietveld Refinement using FullProf Software |CIF file| VESTA Soft| Crystal Struct).
Youtube Link: https://youtu.be/bYjJY2CSJjs
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