Low-temperature magnetization of submonolayer 3He adsorbed on HD preplated graphite

NMR studies of submonolayer 3He adsorbed on a bilayer of HD preplated graphite have been made down to 100 &mgr;K, which is more than 1 order of magnitude smaller than the exchange energy ( J). In the highly frustrated antiferromagnetic solid region, the magnetization obeys a Curie-Weiss law even at temperatures around J and then increases gradually down to 100 &mgr;K. Nevertheless, it does not show any anomalous behavior corresponding to a spin gap. The normalized magnetization versus the reduced temperature ( T/J) is independent of the density just after solidification. This is consistent with the result in the high-temperature region, that the main multiple-spin exchanges have a similar density dependence.