What is long range magnetic order?

[hejun8035]

Hello everyone!
What is long range magnetic order?
Is there any long range magnetic order along the junction when we consider spin polarization?

[zh]

As explained here:
http://hyperphysics.phy-astr.gsu.edu/hbase/solids/ferro.html#c2

The long range magnetic order usually creates magnetic domain.

To study the magnetic properties, the spin polarization must be considered. But when we do spin polarization, all possible magnetic orders should be considered, in principle, to find out the most stable one. To consider long range magnetic order, maybe very large supercell size are needed.  In a word,  spin polarization   =\  long range magnetic order.