Calculating the magnetocrystalline anisotropy (wien mailing list)

[Wien] Magnetocrystalline anisotropy

Xavier Rocquefelte Tue, 09 Jan 2018 00:45:34 -0800

Dear Colleagues

I recently obtained a surprising result concerning the calculation of the magnetocrystalline anisotropy energy (MAE) of SeCuO3.

This compound has a monoclinic symmetry (SG. P21/n) and is known to beantiferromagnetically ordered at low temperature.

Here I provide the results obtained for two magnetic orders, named FM and AFM1 (see attached document) :

https://filesender.renater.fr/?s=download&token=1da93a22-9592-3a7e-ba2e-1533fcae45d2

These calculations have been done using WIEN2k_17, GGA = PBE, RKMAX = 6, kmesh = 5 4 4 and in P1 symmetry. The results are the same using RKMAX = 7.

The AFM1 order is the more stable one, as expected.

However, as shown in the document the MAE of AFM1 order is not symmetric, which is not expected. In contrast the MAE for FM order is symmetric.

Based on the recent discussion "zigzag potential", it seems to me that the AFM1 MAE should be symmetric, because the magnetic moment is a pseudo-vector. Is it possible that the present problem is related to the fact that in the present implementation of the spin-orbit coupling we neglect the off-diagonal terms? Do you have any idea about the problem we are facing? Does someone observe such unusual MAE for other systems?

Best Regards

Xavier

The answers are in the following link:

https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg16962.html