Transverse field Ising ferromagnetism in Mn-12-acetate-MeOH

We report measurements of the magnetic susceptibility of single crystals of Mn-12-acetate-MeOH, a newly-synthesized 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.