  We report measurements of the magnetic susceptibility of single crystals of
Mn$_{12}$-acetate-MeOH, a new high-symmetry variant of the original single
molecule magnet Mn$_{12}$-acetate. A comparison of these data to theory and to
data for the Mn$_{12}$ acetate material shows that Mn$_{12}$-acetate-MeOH is a
realization of a transverse-field Ising ferromagnet in contrast to the original
Mn$_{12}$ acetate material, in which solvent disorder leads to effects
attributed to random field Ising ferromagnetism.

Materials Science