Energy Level Lifetimes in the Single-Molecule Magnet Fe_8 : Experiments and Simulations

Abstract

We present pump-probe measurements on the single-molecule magnet Fe_8 with microwave pulses having a length of several nanoseconds. The microwave radiation in the experiments is located in the frequency range between 104 GHz and 118 GHz. The dynamics of the magnetization of the single Fe_8 crystal is measured using micrometer-sized Hall sensors. This technique allows us to determine the level lifetimes of excited spin states, that are found to be in good agreement with theoretical calculations. The theory, to which we compare our experimental results, is based on a general spin-phonon coupling formalism, which involves spin transitions between nearest and next-nearest energy levels. We show that good agreement between theory and experiments is only obtained when using both the Delta m_S = +-1 transition as well as Delta m_S = +-2, where Delta m_S designates a change in the spin quantum number m_S. Temperature dependent studies of the level lifetimes of several spin states allow us finally to determine experimentally the spin-phonon coupling constants.

6 pages, 5 figures

References in corpus (21)

• Quantum Computing in Molecular Magnets
• Will spin-relaxation times in molecular magnets permit quantum information processing?
• Thermally Activated Resonant Magnetization Tunneling in Molecular Magnets: Mn_12Ac and others
• Molecular engineering of antiferromagnetic rings for quantum computation
• Low-Temperature Quantum Relaxation in a System of Magnetic Nanomolecules
• Observation of the distribution of molecular spin states by resonant quantum tunneling of the magnetization
• Spin Tunneling and Phonon-assisted Relaxation in Mn12-acetate
• Pair-wise decoherence in coupled spin qubit networks
• Quantum Coherence between High Spin Superposition States of Single Molecule Magnet Ni${}_4$
• Photon-assisted tunneling in a Fe8 Single-Molecule Magnet
• Role of dipolar and exchange interactions in the positions and widths of EPR transitions for the single-molecule magnets Fe8 and Mn12
• Coherence Window in the dynamics of Quantum Nanomagnets
• Resonant photon absorption in the low spin molecule V15
• Magnetization dynamics in the single-molecule magnet Fe8 under pulsed microwave irradiation
• Characterization of the S = 9 excited state in Fe8Br8 by Electron Paramagnetic Resonance
• Photon-Induced Magnetization Reversal in Single-Molecule Magnets
• Pump-Probe Experiments on the Single-Molecule Magnet Fe8 : Measurement of Excited Level Lifetimes
• Giant isotope effect in the incoherent tunneling specific heat of the molecular nanomagnet Fe8
• Non-equilibrium Magnetization Dynamics in the Fe_8 Single-Molecule Magnet Induced by High-Intensity Microwave Radiation
• Magnetization and EPR studies of the single molecule magnet Ni${}_4$ with integrated sensors
• Photon-Induced Magnetization Changes in Single-Molecule Magnets

Cited by in corpus (6)

• Single-molecule Nanomagnets
• Tuning Magnetic Avalanches in Mn12-ac
• Magnetization relaxation in the single molecule magnet Ni${}_4$ under continuous microwave irradiation
• Density Matrix Equation for a Bathed Small System and its Application to Molecular Magnets
• Manipulating spins of magnetic molecules: Hysteretic behavior with respect to bias voltage
• Energy emanating from the molecular nanomagnet Fe${}_8$ revisited