I want to do a simple SCF calculation for an entropy stabilised oxide using VASP (DFT code). The chemical formula is (CuCoMgNiZn)O (Rock salt structure) and it is anti-ferromagnetic in nature. I am using the mcsqs code from ATAT (Alloy theoretic automated toolkit) as the structure needs to be random in nature. But the problem is I am getting the overall magnetic moment as 4 (after the DFT calculation) which should ideally be 0 for an anti-ferromagnetic system.

I found one paper stating "As the magnetic structure of the rocksalt (MgCoNiCuZn)O is antiferromagnetic in its ground state, we also considered the arrangement of atomic spins where (111) planes contain magnetic moments alternatively parallel and antiparallel with the spin direction along [211]. Each cation is equally populated in the two magnetic sites: (Mg0.2 Co0.1(spin-up) Co0.1(spin-down) Ni0.1(spin-up) Ni0.1(spin-down) Cu0.2 Zn0.2)O" to deal with the magnetism. The link to the paper https://www.nature.com/articles/s41524-022-00780-0.

The magnetic moment portion of my input file is copied here for your reference.

MAGMOM = 4x0 2x3 2x-3 20x0 2x4 2x-4 4x0 4x0

0 = magnetic moment of Mg, O, Zn,Cu, 3 = magnetic moment of Ni, 4 = magnetic moment of Co

Order of atoms in the POSCAR = Mg Ni O Co Zn Cu

I think there is an issue with the way I write the order of the magnetic moment. But I don't know how to deal with this issue.

Any suggestions would be highly appreciable.

  • 1
    $\begingroup$ Perhaps you may try to use a larger super cell instead. Some complicated antiferromagnetic materials may be erroneously predicted as ferromagnetic, when the periodic cell is not large enough to describe the periodicity of the spins (which may require a larger cell than what would be required to describe the spatial periodicity). Your case is even worse because the structure is aperiodic, which means that a too small cell can have a nonzero magnetic moment solely due to statistical fluctuation, even if the whole material is antiferromagnetic. $\endgroup$
    – wzkchem5
    Jun 12, 2022 at 15:37
  • $\begingroup$ Thank you @wzkchem5. I will try your suggested way. $\endgroup$ Jun 13, 2022 at 18:41
  • $\begingroup$ I gave my +1 long ago, but I just wanted to check how things are going now. When you tried it the way that wzkchem5 suggested, did it work? Have you made any progress since June 2022? Are you still working on it? Please update us! $\endgroup$ Feb 6, 2023 at 20:36


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