In-Field and Zero-Field Relaxation Dynamics of Dysprosocenium in Solution.

Most of the work in expanding the frontiers of single-molecule magnets employs the chemical design of new molecules to increase the size of the effective barrier (Ueff) or the hysteresis temperature (TH). Here we explore how perturbing the local environment affects magnetic relaxation properties by dissolving [Dy(Cpttt)2][B(C6F5)4] in two different solvents: difluorobenzene (DFB) and dichloromethane (DCM). Surprisingly, we find no significant effects in the phonon-driven Raman-I regime at higher temperatures, but we do observe that the frozen-solution environment increases the rate of quantum tunneling of the magnetization (QTM) due to an increase in the size of the avoided level crossing. We find that there is a drastic decrease in the Raman relaxation rate at low temperatures for the concentrated DCM and polycrystalline samples under the applied magnetic field where the QTM process is quenched, which is attributed to changes in the low-energy phonon spectrum and is not replicated for the other samples.