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Related papers: Fronts of spin tunneling in molecular magnets

200 papers

The phenomenon of Quantum Tunneling of Mesoscopic Spins is reviewed in the light of the behavior of the archetype of these systems: the molecular complex Mn12-ac. Most observations can be understood in the framework of the reduced Hilbert…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 B. Barbara , I. Chiorescu , R. Giraud , A. G. M. Jansen , A. Caneschi

Using micron-sized Hall sensor arrays to obtain time-resolved measurements of the local magnetization, we report a systematic study in the molecular magnet Mn$_{12}$-acetate of magnetic avalanches controllably triggered in different fixed…

Materials Science · Physics 2013-05-29 S. McHugh , Bo Wen , Xiang Ma , M. P. Sarachik , Y. Myasoedov , E. Zeldov , R. Bagai , G. Christou

We study the spin polarization of tunneling holes injected from ferromagnetic GaMnAs into a p-doped semiconductor through a tunneling barrier. We obtain an upper limit to the spin injection rate. We find that spin-orbit interaction…

Mesoscale and Nanoscale Physics · Physics 2016-08-31 L. Brey , J. Fernandez-Rossier , C. Tejedor

The magnetic instability at the front of the spin avalanche in a crystal of molecular magnets is considered. This phenomenon reveals similar features with the Darrieus-Landau instability, inherent to classical combustion flame fronts. The…

Mesoscale and Nanoscale Physics · Physics 2016-04-15 O. Jukimenko , M. Modestov , C. M. Dion , M. Marklund , V. Bychkov

Below 360 mK, Fe magnetic molecular clusters are in the pure quantum relaxation regime and we show that the predicted square-root time relaxation is obeyed, allowing us to develop a new method for watching the evolution of the distribution…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 W. Wernsdorfer , T. Ohm , C. Sangregorio , R. Sessoli , D. Mailly , C. Paulsen

The ground state of colloidal magnetic particles in a modulated channel are investigated as function of the tilt angle of an applied magnetic field. The particles are confined by a parabolic potential in the transversal direction while in…

Soft Condensed Matter · Physics 2014-04-02 J. E. Galván-Moya , D. Lucena , W. P. Ferreira , F. M. Peeters

We consider theoretically transport in a spinfull one-channel interacting quantum wire placed in an external magnetic field. For the case of two point-like impurities embedded in the wire, under a small voltage bias the spin-polarized…

Strongly Correlated Electrons · Physics 2010-02-17 Zoran Ristivojevic , George I. Japaridze , Thomas Nattermann

We report time-resolved measurements of magnetization switching by spin-orbit torques in the absence of an external magnetic field in perpendicularly magnetized magnetic tunnel junctions (MTJ). Field-free switching is enabled by the dipolar…

Mesoscale and Nanoscale Physics · Physics 2020-06-12 Viola Krizakova , Kevin Garello , Eva Grimaldi , Gouri Sankar Kar , Pietro Gambardella

The dynamical theory of thermally activated resonant magnetization tunneling in uniaxially anisotropic magnetic molecules such as Mn_12Ac (S=10) is developed.The observed slow dynamics of the system is described by master equations for the…

Statistical Mechanics · Physics 2009-10-31 D. A. Garanin , E. M. Chudnovsky

We find that dipolar interactions favor ferromagnetic ordering of elongated crystals of Mn12 Acetate below 0.8 K. Ordered crystals must possess domain walls. Motion of the wall corresponds to a moving front of Landau-Zener transitions…

Statistical Mechanics · Physics 2009-11-13 D. A. Garanin , E. M. Chudnovsky

We consider the possibility of detecting spin precession in a magnetic field by nonequilibrium transport processes. We find that time reversal symmetry imposes strong constraints on the problem. Suppose the tunneling occurs directly between…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 M. B. Hastings

Recent experiments (Decelle et al., Phys. Rev. Lett. 102, 027203 (2009)) discovered an ultra-fast regime of spin avalanches in crystals of magnetic magnets, which was three orders of magnitude faster than the traditionally studied magnetic…

Materials Science · Physics 2015-05-28 M. Modestov , V. Bychkov , M. Marklund

Multi-spins tunneling cross-relaxations in an ensemble of weakly-coupled Ho$^{3+}$ ions, mediated by weak anisotropic dipolar interactions, can be evidenced by ac-susceptibility measurements in a high temperature regime. Based on a…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 R. Giraud , A. M. Tkachuk , B. Barbara

Current theories still fail to give a satisfactory explanation of the observed quantum phenomena in the relaxation of the magnetisation of the molecular cluster Mn12 acetate. In the very low temperature regime, Prokof'ev and Stamp recently…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 W. Wernsdorfer , R. Sessoli , D. Gatteschi

Spin transport in magnetic tunnel junctions in the presence of spin diffusion is considered theoretically. Combining ballistic tunneling across the barrier and diffusive transport in the electrodes, we solve the spin dynamics equation in…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 A Manchon , R. Matsumoto , H. Jaffres , J. Grollier

We report experimental studies of crystals of Mn12 molecular magnetic clusters in pulsed magnetic fields with sweep rates up to 4x10^3 T/s. The steps in the magnetization curve are observed at fields that are shifted with respect to the…

Other Condensed Matter · Physics 2009-11-10 J. Vanacken , S. Stroobants , M. Malfait , V. V. Moshchalkov , M. Jordi , J. Tejada , R. Amigo , E. M. Chudnovsky , D. A. Garanin

We review the present state of theory and experiments on the quantum tunneling of magnetization in mesoscopic spin systems. Most attention is paid to the relaxation of magnetization in the molecular complexes Mn12 and Fe8. The role of the…

Condensed Matter · Physics 2007-05-23 Igor Tupitsyn , Bernard Barbara

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

Resonant behavior involving spin-orbit entangled states occurs for spin transport along a narrow channel defined in a two-dimensional electron gas, including an apparent rapid relaxation of the spin polarization for special values of the…

Mesoscale and Nanoscale Physics · Physics 2014-04-02 D. H. Berman , M. Khodas , M. E. Flatté

Doubly dipolar molecules exhibit complex internal spin-dynamics when electric and magnetic fields are both applied. Near magnetic trap minima, these spin-dynamics lead to enhancements in Majorana spin-flip transitions by many orders of…

Atomic Physics · Physics 2018-01-03 David L. Reens , Hao Wu , Tim Langen , Jun Ye