Self-organization of topological defects for a triangular-lattice   magnetic dots array subject to a perpendicular magnetic field
  The regular array of magnetic particles (magnetic dots) of the form of a two-dimensional triangular lattice in the presence of external magnetic field demonstrates complicated magnetic structures. The magnetic symmetry of the ground state for such a system is lower than that for the underlying lattice. Long range dipole-dipole interaction leads to a specific antiferromagnetic order in small fields, whereas a set of linear topological defects appears with the growth of the magnetic field. Self-organization of such defects determines the magnetization process for a system within a wide range of external magnetic fields. 
R. Khymyn, V. Kireev, B. Ivanov
cond-mat.mes-hall