Quantum Tunneling of the Magnetization in an Iron Cluster Nanomagnet

Sangregorio, Claudio; Ohm, T.; Paulsen, C.; Sessoli, Roberta; Gatteschi, Dante

doi:10.1103/physrevlett.78.4645

Cited by 728 publications

(620 citation statements)

References 22 publications

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“…(1) and diagonalize within the manifold of all the 8-spin configurations yielding states with S z ¼ 0; there are 1286 energy eigenvalues corresponding to eigenvectors with S ranging from 0 to 10. The distribution of states is: (10,1), (9,7), (8,24), (7,56), (6,104), (5,164), (4,220), (3,248), (2,232), (1,168), (0,62), where the first number in parenthesis is the value of S and the second is the number of levels with this value of S: With the 2S þ 1 degeneracies included, there are exactly 10 000 states. These are the basis states which are then used to diagonalize the full Hamiltonian, including anisotropy and DM terms.…”

Section: -Spin Model Of Mnmentioning

confidence: 99%

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Many-spin effects and tunneling splittings in Mn12 magnetic molecules

Raedt

Hams

Dobrovitski

et al. 2002

Journal of Magnetism and Magnetic Materials

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Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. AbstractWe calculate the tunneling splittings in a Mn 12 magnetic molecule taking into account its internal many-spin structure. We discuss the precision and reliability of these calculations and show that restricting the basis (limiting the number of excitations taken into account) may lead to significant error (orders of magnitude) in the resulting tunneling splittings for the lowest energy levels, so that an intuitive picture of different decoupled energy scales does not hold in this case. ; and, at present, a substantial amount of reliable experimental data has been collected. Quantitative analysis of these experiments is a challenging theoretical problem involving fundamental issues about tunneling phenomena in mesoscopic magnetic systems. The basic prerequisite for solving this problem is our ability to evaluate accurately and reliably the energy splittings occurring as a result of tunneling between two (quasi) degenerate levels [7]. At present, carefully designed magnetic relaxation

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Section: -Spin Model Of Mnmentioning

confidence: 99%

“…A number of impressive experimental results have been obtained recently, such as thermally assisted tunneling [2,3], ground state-to-ground state tunneling [4,6] and topological phase effects in spin tunneling [4]. Among others, the molecular magnet 12 ) has received special attention.…”

Section: Introductionmentioning

confidence: 99%

Many-spin effects and tunneling splittings in Mn12 magnetic molecules

Raedt

Hams

Dobrovitski

et al. 2002

Journal of Magnetism and Magnetic Materials

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“…1,2,3,4 At low temperature, T , each SMM behaves approximately as a single spin S. Magnetic relaxation at k B T 0.1U/S, where U is a magnetocrystalline anisotropy barrier, is temperature independent, and is duly attributed to quantum tunneling under the barrier. Hyperfine interactions with nuclear spins as well as dipole-dipole interactions among all SMM electronic spins give rise to a variety of phenomena that are not yet fully understood.…”

Section: Introductionmentioning

confidence: 99%

Time relaxation of interacting single-molecule magnets

Fernández

Alonso

2005

Phys. Rev. B

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We study the relaxation of interacting single-molecule magnets (SMMs) in both spatially ordered and disordered systems. The tunneling window is assumed to be, as in Fe 8 , much narrower than the dipolar field spread. We show that relaxation in disordered systems differs qualitatively from relaxation in fully occupied cubic and Fe 8 lattices. We also study how line shapes that develop in "hole-digging" experiments evolve with time t in these fully occupied lattices. We show (1) that the dipolar field h scales as t p in these hole line shapes and show (2) how p varies with lattice structure. Line shapes are not, in general, Lorentzian. More specifically, in the lower portion of the hole, they behave as (| h | /t p ) (1/p)−1 if h is outside the tunnel window. This is in agreement with experiment and with our own Monte Carlo results.

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“…Such systems lie at the interface between classical and quantum-mechanical regimes, and are thus of great fundamental as well as practical interest regarding future applications related to quantum computing. 1 Molecular clusters such as Mn 12 , 2,3,4,5 Fe 8 , 6 and Mn 4 7 have been found to exhibit hysteresis curves characterized by a remanence. They have been dubbed singlemolecule magnets (SMMs) as each molecule behaves as a single-domain nanomagnetic particle.…”

Section: Introductionmentioning

confidence: 99%

Phonon bottleneck effect leads to observation of quantum tunneling of the magnetization and butterfly hysteresis loops in(Et4N)3Fe2
Schenker
¹
,
Leuenberger
²
,
Chaboussant
³

et al. 2005
Phys. Rev. B

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A detailed investigation of the unusual dynamics of the magnetization of (Et4N)3Fe2F9 (Fe2), containing isolated [Fe2F9] 3− dimers, is presented and discussed. Fe2 possesses an S = 5 ground state with an energy barrier of 2.40 K due to an axial anisotropy. Poor thermal contact between sample and bath leads to a phonon bottleneck situation, giving rise to butterfly-shaped hysteresis loops below 5 K concomitant with slow decay of the magnetization for magnetic fields Hz applied along the Fe-Fe axis. The butterfly curves are reproduced using a microscopic model based on the interaction of the spins with resonant phonons. The phonon bottleneck allows for the observation of resonant quantum tunneling of the magnetization at 1.8 K, far above the blocking temperature for spin-phonon relaxation. The latter relaxation is probed by AC magnetic susceptibility experiments at various temperatures and bias fields HDC. At HDC = 0, no out-of-phase signal is detected, indicating that at T ≥ 1.8 K Fe2 does not behave as a single-molecule magnet. At HDC = 1 kG, relaxation is observed, occurring over the barrier of the thermally accessible S = 4 first excited state that forms a combined system with the S = 5 state.

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Quantum Tunneling of the Magnetization in an Iron Cluster Nanomagnet

Cited by 728 publications

References 22 publications

Many-spin effects and tunneling splittings in Mn12 magnetic molecules

Many-spin effects and tunneling splittings in Mn12 magnetic molecules

Time relaxation of interacting single-molecule magnets

Phonon bottleneck effect leads to observation of quantum tunneling of the magnetization and butterfly hysteresis loops in(Et4N)3Fe2
Schenker
¹
,
Leuenberger
²
,
Chaboussant
³

et al. 2005
Phys. Rev. B

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Quantum Tunneling of the Magnetization in an Iron Cluster Nanomagnet

Cited by 728 publications

References 22 publications

Many-spin effects and tunneling splittings in Mn12 magnetic molecules

Many-spin effects and tunneling splittings in Mn12 magnetic molecules

Time relaxation of interacting single-molecule magnets

Phonon bottleneck effect leads to observation of quantum tunneling of the magnetization and butterfly hysteresis loops in(Et4N)3Fe2Schenker1, Leuenberger2, Chaboussant3 et al. 2005Phys. Rev. B

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Phonon bottleneck effect leads to observation of quantum tunneling of the magnetization and butterfly hysteresis loops in(Et4N)3Fe2
Schenker
¹
,
Leuenberger
²
,
Chaboussant
³

et al. 2005
Phys. Rev. B