For Co2FeSn, I have generated the diffraction reflections through Vesta but I am facing having a problem with its B2 and A2 structures.
B2 phase has Pm-3m symmetry(221) while A2 has Im-3m symmetry(229), from what I understand, both should give different peak positions though the same system. I am facing problem in finding its standard CIF database. KINDLYYY HEEELLPPP
Hello, Abegail Yimchunger.
When you generated a pattern through VESTA, what structure did you use?
For A2 and B2 structures, you may have similar chemical composition, but the structure must be different, because they are primitive and body-centered cubic. Do you have any reference for the description of these structures?
Sincerely,
Ricardo Tadeu
Ricardo Tadeu Maia, I tried for L21, B2, and A2, but the structure generated from Vesta when edited to B2&A2 does not seem so convincing with the structures that were described in kinds of literature.
Article All-d-Metal Heusler Alloys: A Review
Article Equiatomic quaternary Heusler alloys: A material perspective...
Article Transport properties of Heusler compounds and alloys
I think I understood what you got.
Check the Table 1 for the article you cited All-d-Metal Heusler Alloys: A Review.
It says that you have 4 kinds of sites (A, B, C, D) and 4 atoms in the general formula X2YZ.
For L21 structure, you can only have A and C sites occupied by X. B site is occupied by Y, and D site occupied by Z. This leads to a Fm-3m structure.
For B2, you continue with A and C occupied by X, but B and D can now be occupied by Y and Z, which leads to a lower symmetry. And for A2, you can have all of the atoms occupying all the sites, as described in 10.1063/1.4959093
Check Figure 3 from this article, you can visualize better:
10.1002/adma.201201879
Thankyou, I got it.
In VESTA, we can edit the symmetry like from Fm3-m to Pm3-m, however when done so for B2 & A2, the structure is not compatible with the literature and thus the diffraction pattern generated is suspicious.
Hello.
You have to be careful with space group transformation in VESTA, it's not straightforward. There is a proper way to "convert" between the groups but I don't know how to do it. I think that the point is the possibilities of structures that can be generated when you let X, Y and Z occupy any site. If you model a non symmetrical structure, the pattern will become different from cubic
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