Spin correlation and relaxational dynamics in molecular-based single-chain magnets

We report the combined measurements of the dc susceptibility chi(0), the ac susceptibility chi('), and the NMR relaxation rate T-1(-1) for the molecular-based heterometallic single-chain magnet [Mn(saltmen)](2)[Ni(pao)(2)(py)(2)](PF6)(2). At low temperatures, this system is well described by a one-dimensional array of effective spin S=3 chains comprising the Mn-III-Ni-II-Mn-III trimers and treated as the S=3 Ising chain with the single-ion term (Blume-Capel model). Using the exact solution of the model and based on the picture that the random motion of the local domain walls dominates the low-temperature spin dynamics, we succeeded in reproducing the experimental results of the dc susceptibility chi(0), the ac susceptibility chi('), and the F-19-NMR relaxation rate T-1(-1) in a consistent manner.