# Sm2Fe17 ID: mp-1426

Dear Expert

I would like to get some help regarding the calculation of Sm2Fe17 are
Final Magnetic Moment 5.436 μB Magnetic Ordering FiM.
The experimental magnetization of this compound is 25μB/F.U. and they mention it is ferromagnetic please see that
Q. Wang, X.P. Zhong, H.L. Luo, J. Magn. Magn. Mater. 110 (1992) 170.

May be I am missing something in the calculation
I hope you can clarify that to me
Thanks in advance for all the effort and time

You can retrieve the full structure with associated magnetic moments via the API:

``````Full Formula (Sm2 Fe17)
Reduced Formula: Sm2Fe17
abc   :   6.438282   6.438282   6.438283
angles:  82.951010  82.951010  82.951005
Sites (19)
#  SP            a          b          c    magmom
---  ----  ---------  ---------  ---------  --------
0  Sm     0.65881    0.65881    0.65881     -0.306
1  Sm     0.34119    0.34119    0.34119     -0.306
2  Fe    -0         -0          0.5          2.157
3  Fe    -0          0.5       -0            2.131
4  Fe     0.5       -0         -0            2.111
5  Fe     0.291307   0.708693  -0            2.478
6  Fe     0.708693   1          0.291307     2.454
7  Fe     0          0.291307   0.708693     2.441
8  Fe     0.291307   0          0.708693     2.454
9  Fe     1          0.708693   0.291307     2.441
10  Fe     0.708693   0.291307  -0            2.478
11  Fe     0.34279    0.34279    0.845362     2.411
12  Fe     0.34279    0.845362   0.34279      2.379
13  Fe     0.845362   0.34279    0.34279      2.365
14  Fe     0.65721    0.65721    0.154638     2.411
15  Fe     0.65721    0.154638   0.65721      2.379
16  Fe     0.154638   0.65721    0.65721      2.365
17  Fe     0.903488   0.903488   0.903488     2.65
18  Fe     0.096512   0.096512   0.096512     2.65
``````

This actually gives a total moment of around 40 µB.

I can only conclude the current magnetic moment reported on the website is in error, this will be fixed. For now, I advise using the API to get this information.

Best,

Matt

Thanks to @shyamd for helping investigate. It looks like the total magnetization currently reported is for an older calculation:

``````Full Formula (Sm2 Fe17)
Reduced Formula: Sm2Fe17
abc   :   6.445764   6.445764   6.445763
angles:  83.033313  83.033313  83.033303
Sites (19)
#  SP           a         b         c    magmom
---  ----  --------  --------  --------  --------
0  Sm    0.340619  0.340619  0.340619     0.033
1  Sm    0.659381  0.659381  0.659381     0.033
2  Fe    0.657508  0.155042  0.657508     0.055
3  Fe    0.657508  0.657508  0.155042     0.073
4  Fe    0.903549  0.903549  0.903549    -0.043
5  Fe    0.096451  0.096451  0.096451    -0.043
6  Fe    0         0.5       0           -2.026
7  Fe    0.5       0         0           -2.038
8  Fe    0         0         0.5         -2.087
9  Fe    0.708104  0         0.291896     0.05
10  Fe    0         0.291896  0.708104     0.052
11  Fe    0.291896  0.708104  0            0.015
12  Fe    0.291896  0         0.708104     0.05
13  Fe    0         0.708104  0.291896     0.052
14  Fe    0.708104  0.291896  0            0.015
15  Fe    0.342492  0.342492  0.844958     0.073
16  Fe    0.342492  0.844958  0.342492     0.055
17  Fe    0.844958  0.342492  0.342492     0.057
18  Fe    0.155042  0.657508  0.657508     0.057
``````

In this particular case, the total magnetization was incorrectly reported from an older calculation that relaxed in an unphysical way, as shown above. Our upcoming database release will fix the issue for this material. The calculation reported should have been the one with the 40 µB value.

Note that this is still different from the experimental value of 25 µB per formula unit that you cited, however this is an issue with DFT GGA theory itself, and is a limitation of this level of theory.

Hi Mkhorton
Thank you very much for your quick and very clear answer. Appreciate all the clarification by you and your team. Now I should stick with magnetic ordering FM and I am doing calculation with wien2k hope results will meet the experimental cited value of 25 µB per formula unit.
Thank you again and please accept my best regards.

Inconsistent magnetic moments have been addressed, https://materialsproject.org/materials/mp-1426/ now correctly shows 40 µB