Geometric-phase interference in a Mn_{12} single-molecule magnet with four-fold rotational symmetry

Abstract

We study the magnetic relaxation rate Gamma of the single-molecule magnet Mn_{12}-tBuAc as a function of magnetic field component H_T transverse to the molecule's easy axis. When the spin is near a magnetic quantum tunneling resonance, we find that Gamma increases abruptly at certain values of H_T. These increases are observed just beyond values of H_T at which a geometric-phase interference effect suppresses tunneling between two excited energy levels. The effect is washed out by rotating H_T away from the spin's hard axis, thereby suppressing the interference effect. Detailed numerical calculations of Gamma using the known spin Hamiltonian accurately reproduce the observed behavior. These results are the first experimental evidence for geometric-phase interference in a single-molecule magnet with true four-fold symmetry.

version accepted by PRL; added inset to Fig. 1, added three references and a footnote; other minor changes; 5 pages, 4 figures

References in corpus (26)

• Thermally Activated Resonant Magnetization Tunneling in Molecular Magnets: Mn_12Ac and others
• Suppression of tunneling by interference in half-integer--spin particles
• Destructive quantum interference in spin tunneling problems
• Spin Tunneling and Phonon-assisted Relaxation in Mn12-acetate
• The origin of second-order transverse magnetic anisotropy in Mn12-acetate
• Spin-parity dependent tunneling of magnetization in single-molecule magnets
• Single-molecule Nanomagnets
• Berry Phase Oscillations of the Kondo Effect in Single-Molecule Magnets
• Quantum phase interference and spin parity in Mn12 single-molecule magnets
• Spin relaxation in Mn12-acetate
• Symmetry of Magnetic Quantum Tunneling in Single Molecule Magnet Mn12-acetate
• Aharonov-Casher-Effect Suppression of Macroscopic Tunneling of Magnetic Flux
• Quantum Phase Interference and Neel-Vector Tunneling in Antiferromagnetic Molecular Wheels
• Diabolical Points in Magnetic Molecules: An Exactly Solvable Model
• Berry phase, topology, and diabolicity in quantum nano-magnets
• Influence of the Dzyaloshinskii-Moriya exchange interaction on quantum phase interference of spins
• SU(2) instantons with boundary jumps and spin tunneling in magnetic molecules
• Quenched Spin Tunneling and Diabolical Points in Magnetic Molecules: II. Asymmetric Configurations
• Quenched Spin Tunneling and Diabolical Points in Magnetic Molecules: I. Symmetric Configurations
• Non-Kramers Freezing and Unfreezing of Tunneling in the Biaxial Spin Model
• Geometric-Phase-Effect Tunnel-Splitting Oscillations in Single-Molecule Magnets with Fourth-Order Anisotropy Induced by Orthorhombic Distortion
• Diabolical points in the magnetic spectrum of Fe_8 molecules
• Magneto-elastic waves in crystals of magnetic molecules
• Crystal Field -AS_z^2 Does Not Produce One-Phonon Transitions With Delta S_z=+-2 [Comment on EPL 46, 692 (1999) by Leuenberger and Loss]
• Reply to the comment of Chudnovsky&Garanin on "Spin relaxation in Mn12-acetate"
• Density Matrix Equation for a Bathed Small System and its Application to Molecular Magnets

Cited by in corpus (8)

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• Dynamic spin localization and gamma-magnets
• Three-Leaf Quantum Interference Clovers in a Trigonal Single-Molecule Magnet
• Effects of uniaxial pressure on the quantum tunneling of magnetization in a high-symmetry Mn12 single-molecule magnet
• Precision ESR Measurements of Transverse Anisotropy in the Single-molecule Magnet Ni${}_4$
• Unraveling the switching dynamics in a quantum double-well potential
• Direct Spectroscopic Observation of Berry Phase Interference in the Ni${}_4$ Single-Molecule Magnet