Abstract
Electron paramagnetic resonance measurements on single crystals of the molecular magnets and reveal complex nonlinearities in the linewidths as functions of energy eigenstate, frequency, and temperature. Using a density-matrix equation with distributions of the uniaxial anisotropy parameter D, the Landé g factor, and dipolar interactions, we obtain linewidths in good agreement with experiments. Our study shows that the distribution in D is common to the examined molecular magnets and regardless of the qualities of the samples. This could provide the basis for a proposed tunneling mechanism due to lattice defects. The distribution in g is also quite significant for
- Received 20 August 2001
DOI:https://doi.org/10.1103/PhysRevB.65.014426
©2001 American Physical Society