NUCLEAR MAGNETISM OF 2-DIMENSIONAL SOLID HE-3 ADSORBED ON PLATED GRAPHITE

Nuclear spin exchange in the lour density two dimensional quantum soli d formed by He-3 adsorbed on graphite plated by a bilayer of HD has be en studied by heat capacity and magnetization measurements. The low de nsities result in a frustrated magnet with significantly larger effect ive exchange constants than observed in the antiferromagnetic second l ayer of He-3 on bare graphite. Promotion to a fluid overlayer occurs a t 6.8 nm(-2). A ferromagnetic anomaly is observed in magnetization mea surements at 10 nm(-2) with an effective exchange constant of 1.0 mK, about half the value observed at the corresponding anomaly on bare gra phite.