Tunneling Splittings in Mn12-Acetate Single Crystals

Abstract

A Landau-Zener multi-crossing method has been used to investigate the tunnel splittings in high quality Mn${}_{12}$-acetate single crystals in the pure quantum relaxation regime and for fields applied parallel to the magnetic easy axis. With this method several individual tunneling resonances have been studied over a broad range of time scales. The relaxation is found to be non-exponential and a distribution of tunnel splittings is inferred from the data. The distributions suggest that the inhomogeneity in the tunneling rates is due to disorder that produces a non-zero mean value of the average transverse anisotropy, such as in a solvent disorder model. Further, the effect of intermolecular dipolar interaction on the magnetic relaxation has been studied.

Europhysics Letters (in press). 7 pages, including 3 figures

References in corpus (7)

• Effects of D-strain, g-strain, and dipolar interactions on EPR linewidths of the molecular magnets Fe8 and Mn12
• Detailed single crystal EPR lineshape measurements for the single molecule magnets Fe8Br and Mn12-ac
• Spin tunneling via dislocations in Mn-12 acetate crystals
• Dislocation-induced spin tunneling in Mn-12 acetate
• A Distribution of Tunnel Splittings in Mn${}_{12}$-Acetate
• Quantum Step Heights in Hysteresis Loops of Molecular Magnets
• Quadratic transverse anisotropy term due to dislocations in Mn12-Ac directly obtained by EPR spectroscopy

Cited by in corpus (7)

• Definitive spectroscopic determination of the transverse interactions responsible for the magnetic quantum tunneling in Mn12-acetate
• Symmetry of Magnetic Quantum Tunneling in Single Molecule Magnet Mn12-acetate
• Second-order transverse magnetic anisotropy induced by disorders in the single-molecule magnet Mn12
• 'Hole-digging' in ensembles of tunneling Molecular Magnets
• Quantum dynamics of a nanomagnet in a rotating field
• Observation of a Distribution of Internal Transverse Magnetic Fields in a Mn12-Based Single Molecule Magnet
• Incoherent Landau-Zener-Stuckelberg Transitions in Single-Molecule Magnets