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Related papers: Phonoemissive Spin Tunneling in Molecular Nanomagn…

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We report measurements on magnetization reversal in the Fe$_8$ molecular magnet using fast pulsed magnetic fields of 1.5 kT/s and in the temperature range of 0.6-4.1 K. We observe and analyze the temperature dependence of the reversal…

Mesoscale and Nanoscale Physics · Physics 2014-09-11 S. N. Jammalamadaka , J. Vanacken , V. V. Moshchalkov , Saül Vélez , J. Tejada , Ferran Macià

We present a theory of the low-energy excitations of a ferromagnetic metal nanoparticle. In addition to the particle-hole excitations, which occur in a paramagnetic metal nanoparticle, we predict a branch of excitations involving the…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 C. M. Canali , A. H. MacDonald

We present a comprehensive theory of the magnetization relaxation in a Mn12-acetate crystal in the high-temperature regime (T>1 K), which is based on phonon-assisted spin tunneling induced by quartic magnetic anisotropy and weak transverse…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Michael N. Leuenberger , Daniel Loss

Quantum tunneling of the magnetization is a phenomenon that impedes the use of small anisotropic spin systems for storage purposes even at the lowest temperatures. Phonons, usually considered for temperature dependent relaxation of…

Strongly Correlated Electrons · Physics 2021-04-07 K. Irländer , H. -J. Schmidt , J. Schnack

We study the magnetic relaxation of a system of localized spins interacting through weak dipole interactions, at a temperature large with respect to the ordering temperature but low with respect to the crystal field level splitting. The…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 A. Cuccoli , A. Fort , A. Rettori , E. Adam , J. Villain

The magnetization reversal in a single molecular magnet (SMM) weakly coupled to an electrode with spin-dependent splitting of chemical potentials (spin bias) is theoretically investigated by means of the rate equation. A microscopic…

Mesoscale and Nanoscale Physics · Physics 2009-05-14 Hai-Zhou Lu , Bin Zhou , Shun-Qing Shen

We present measurements on the single molecule magnet Fe8 in the presence of pulsed microwave radiation at 118 GHz. The spin dynamics is studied via time resolved magnetization experiments using a Hall probe magnetometer. We investigate the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 K. Petukhov , S. Bahr , W. Wernsdorfer , A. -L. Barra , V. Mosser

High energy resolution spectroscopic studies of quantum magnets have proven to be extremely valuable in directly accessing magnetodynamics quantities, such as energy barriers, magnetic interactions, lifetime of excited states and…

Mesoscale and Nanoscale Physics · Physics 2022-02-17 Sascha Brinker , Felix Küster , Stuart S. P. Parkin , Paolo Sessi , Samir Lounis

A magnet with precessing magnetization pumps a spin current into adjacent leads. As a special case of this spin pumping, a precessing macrospin (magnetization) can assist electrons in tunneling. In small systems, however, the Coulomb…

Mesoscale and Nanoscale Physics · Physics 2021-06-09 Tim Ludwig , Rembert A. Duine

Spin coherent state path integrals with discontinuous semiclassical paths are investigated with special reference to a realistic model for the magnetic degrees of freedom in the Fe8 molecular solid. It is shown that such paths are essential…

Condensed Matter · Physics 2009-11-07 Ersin Kececioglu , Anupam Garg

A new quantum approach is presented that can account for the description of small ferromagnetic particles magnetization tunneling. An estimate of the saturation value of an external applied magnetic field along the easy axis is obtained. An…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 D. Galetti , B. M. Pimentel , C. L. Lima , E. C. Silva

Spin reversal in magnetic nanomolecules and nanoclusters is considered. A method is suggested allowing, from one side, to keep for long time magnetic polarization in a metastable state and, from the other side, for starting the reversal…

Mesoscale and Nanoscale Physics · Physics 2022-03-23 V. I. Yukalov , E. P. Yukalova

The nuclear spin-lattice relaxation rate 1/T_1_ is calculated for magnetic ring clusters by fully diagonalizing their microscopic spin Hamiltonians. Whether the nearest-neighbor exchange interaction J is ferromagnetic or antiferromagnetic,…

Strongly Correlated Electrons · Physics 2009-11-11 Shoji Yamamoto , Toshiya Hikihara

The theory for the quantum tunneling of nano-magnets is developed within the intermediate spin framework. Periodic magnetic effects are seen to reflect that associated with a change of flux by a single flux quantum $\Phi_{0}$. Essential are…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 S. E. Barnes

We measure electron tunneling via discrete energy levels in ferromagnetic cobalt particles less than 4 nm in diameter, using non-magnetic electrodes. Due to magnetic anisotropy, the energy of each tunneling resonance shifts as an applied…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 S. Gueron , Mandar M. Deshmukh , E. B. Myers , D. C. Ralph

Electronic transport through a single-molecule magnet Mn$_{12}$ in a two-terminal set up is calculated using the non-equilibrium Green's function method in conjunction with density-functional theory. A single-molecule magnet Mn$_{12}$ is…

Materials Science · Physics 2010-01-28 Salvador Barraza-Lopez , Kyungwha Park , Víctor García-Suárez , Jaime Ferrer

In the field of femtomagnetism magnetic matter is controlled by ultrafast laser pulses; here we show that coupling phonon excitations of the nuclei to spin and charge leads to femto-phono-magnetism, a powerful route to control magnetic…

Materials Science · Physics 2022-03-29 S. Sharma , S. Shallcross , P. Elliott , J. K. Dewhurst

The low temperature spin dynamics of a Fe8 Single-Molecule Magnet was studied under circularly polarized electromagnetic radiation allowing us to establish clearly photon-assisted tunneling. This effect, while linear at low power, becomes…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 L. Sorace , W. Wernsdorfer , C. Thirion , A. -L. Barra , M. Pacchioni , D. Mailly , B. Barbara

We introduce a new quantum embedding method to explore spin-phonon interactions in molecular magnets. This technique consolidates various spin/phonon couplings into a limited number of collective degrees of freedom, allowing for a fully…

Quantum Physics · Physics 2024-07-11 Nosheen Younas , Yu Zhang , Andrei Piryatinski , Eric R Bittner

An effective method for ultrafast magnetization reversal of nanoclusters is suggested. The method is based on coupling a nanocluster to a resonant electric circuit. This coupling causes the appearance of a magnetic feedback field acting on…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 V. I. Yukalov , E. P. Yukalova