Two dimensional solid 3He: a frustrated magnetic system

Like in the bcc three-dimensional solid, competing cyclic ring exchanges govern the magnetic properties of 3He films. Three-particle exchange dominates at high and moderate areal density, leading to the ferromagnetic properties previously observed. At the low densities corresponding to the observation of commensurate phases, higher order (four and six-spin) antiferromagnetic exchanges are more important and lead to a frustrated antiferromagnetic system. A variety of anomalies recently observed are interpreted