  We adapt Takahashi's modified spin-wave theory to the context of
nano-magnets, and apply it to the molecular compound based on the giant
magnetic molecule Mo(72)Fe(30). This involves solving numerically the
mean-field equations and then forcing the sublattice magnetizations to zero by
means of local chemical potentials for the magnons. We have thus constructed a
quantum state with no local magnetization at all temperatures, appropriate to a
finite-size system, but with strong correlations. We compare theoretical
results to specific heat and ESR measurements.
