Magneric dipoles in a plane

Kosterlitz-Thouless transition of magnetic dipoles on the two-dimensional plane.
Seung Ki Baek, Petter Minnhagen, and Beom Jun Kim
Phys. Rev. B 83, 184409 (2011) 

Staggered magnetization and susceptibility for squared (left) and honeycomb (right) lattices.