Phononic Resonant Relaxation in Magnetic Hysteresis of Single-Molecule Magnets

Lanthanide-based single-molecule magnets can exhibit broad magnetic hysteresis which basically manifests slow magnetic relaxation in strong magnetic fields. However, the cause of numerous nontrivial hysteresis behaviors remain debated. Here, we put forward two influential mechanisms: the activation of optical-phonon-mediated direct transitions within the ground-state doublet and resonant Raman process. These discoveries, coupled with the g-factor anisotropy, can account for observed hysteresis behaviors in the regimes of fast magnetic relaxation. Our findings substantially complement the recognized mechanisms used to interpret the magnetic hysteresis of single molecule magnets.