Physical Sciences and Mathematics Commons^™

Realization Of Random-Field Ising Ferromagnetism In A Molecular Magnet, Bo Wen, P Subedi, Lin Bo, Y Yeshurun, M P. Sarachik, A D. Kent, A J. Millis, Christos Lampropoulos, G Christou

Chemistry Faculty Research and Scholarship

The longitudinal magnetic susceptibility of single crystals of the molecular magnet Mn₁₂-acetate obeys a Curie-Weiss law, indicating a transition to a ferromagnetic phase at ∼0.9 K. With increasing magnetic field applied transverse to the easy axis, a marked change is observed in the temperature dependence of the susceptibility, and the suppression of ferromagnetism is considerably more rapid than predicted by mean-field theory for an ordered single crystal. Our results can instead be fit by a Hamiltonian for a random-field Ising ferromagnet in a transverse magnetic field, where the randomness derives from the intrinsic distribution of locally tilted magnetic …