Two-dimensional antiferromagnetism of solidHe3adsorbed on plated graphite

Abstract
We report measurements of the nuclear magnetic susceptibility of the monolayer two-dimensional solid formed by He3 adsorbed on graphite plated with two atomic layers of HD. A low-density solid is observed, consistent with a √7 × √7 registered structure, which exhibits large antiferromagnetic exchange. A distinct cusp in the susceptibility is observed near 1 mK, suggestive of a magnetic phase transition. The evolution of this and other features with surface density is discussed.