[Wien] AFM calculation

[Stefaan Cottenier]

> 1 Is it right for my claculational method?

Yes, this seems to be perfectly OK. Out of the 3 elements in your structure
(Bi, Fe, O) only Fe is expected to carry a sizeable moment, which is indeed
what you found:

> :MMINT: MAGNETIC MOMENT IN INTERSTITIAL =    0.00000
> :MMI001: MAGNETIC MOMENT IN SPHERE   1    =   -0.00256(Bi)
> :MMI002: MAGNETIC MOMENT IN SPHERE   2    =    0.00255(Bi)
> :MMI003: MAGNETIC MOMENT IN SPHERE   3    =    3.66726(Fe)
> :MMI004: MAGNETIC MOMENT IN SPHERE   4    =   -3.66725 (Fe)
> :MMI005: MAGNETIC MOMENT IN SPHERE   5    =    0.05963 (O)
> :MMI006: MAGNETIC MOMENT IN SPHERE   6    =   -0.05963 (O)
> :MMTOT: TOTAL MAGNETIC MOMENT IN CELL   =    0.00000

Your two Fe-atoms are antiferromagnetic, just as you wanted them to be.

> 2 I do no kmow why the MAGNETIC MOMENT of the Bi abd O atom is non-zero?

In a compound between 'magnetic' and 'nonmagnetic' elements, never the
moments on the nonmagnetic atoms will be perfectly zero. The magnetic atoms
induce some magnetism on the nonmagnetic ones. For an antiferromagnetic as
you have, these induced moments themselves are antiferromagnetic (one Bi has
a positive moment, the other a negative one, similarly for O). They are two
(O) or three (Bi) orders of magnitude smaller than the Fe moments, in a
qualitative description this is considered as 'zero'.

Stefaan