Is this correct way to determine ferro-magnetism?

[lahaye]

Hi,

I have a unit cell of a dozen atoms, which renders one unpaired
electron in a spin-polarized calculation.

In order to find out how the unpaired spins interact with those
in neighboring unit cells (parallel or anti-parallel), I have doubled
the unit cell, and calculated everything again. Then I get two
unpaired electrons in the "doubled" system.

Now, which of the following statements are true:

1) The unpaired electrons of neighboring unit cells do
not pair up as up/down pairs.

2) This material is ferro-magnetic.

3) This material is not anti-ferro-magnetic.

Thank you for helping me understand this issue.
Rob.

[admin]

please check any standard solid state physics textbook for the definition of ferromagnetic and antiferromagnetic structures!
if the total magnetic moment of the supercell is 0 though each cell carries a magnetic moment, you are in the AF state, ie the moments of neighboring cells couple as up/down (you can check the local moments to verify, set LORBIT appropriately to do so ).