Oedering in Kagomé and squared spins ice

Multi-step ordering in kagome and square artificial spin ice.
C J Olson Reichhardt, A Libál and C Reichhardt
New Journal of Physics 14, 025006 (2012)

Black circles: particle locations; open ellipses: trap locations for a 20a0 ×20a0 section of a kagome ice sample. Colored circles indicate vertex types: N0 (blue), N1 (green), N2 (yellow) and N3 (red). (a) The positive biased ice-rule-obeying state. (b) The monopole state consisting of an ordered lattice of N0 and N3 vertices. (c) A finite-temperature ice-rule-obeying nonbiased state. (d) A high-temperature paramagnetic state where the vertex types are uncorrelated.