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Related papers: Dislocation-induced spin tunneling in Mn-12 acetat…

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The spin-lattice relaxation rate $T_{1}^{-1}$ and NMR spectra of $^1$H in single crystal molecular magnets of Fe8 have been measured down to 15 mK. The relaxation rate $T_1^{-1}$ shows a strong temperature dependence down to 400 mK. The…

Condensed Matter · Physics 2009-11-07 Miki Ueda , Satoru Maegawa , Susumu Kitagawa

We 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…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 H. A. De Raedt , A. H. Hams , V. V. Dobrovitski , M. Al-Saqer , M. I. Katsnelson , B. N. Harmon

We study a possible mechanism of the switching of the magnetic easy axis as a function of hole concentration in (Ga,Mn)As epilayers. In-plane uniaxial magnetic anisotropy along [110] is found to exceed intrinsic cubic magnetocrystalline…

Materials Science · Physics 2009-11-11 K. Hamaya , T. Watanabe , T. Taniyama , A. Oiwa , Y. Kitamoto , Y. Yamazaki

Magnetic relaxation in molecular magnets under a sweeping field is studied by taking into account local stray fields. It is found that the randomness of local stray field leads to a distribution of the relaxation rate which subsequently…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Z. D. Chen , S. Q. Shen

We generalize the Landau-Zener theory of coherent tunneling transitions by taking thermal relaxation into account. The evaluation of a new generalized master equation containing a dynamic tunneling rate that includes the interaction between…

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

The theory of the dislocation motion in the periodic potential relief of the crystal lattice (the Peierls-Nabarro barriers) is reviewed. On the basis of the kink mechanism the temperature dependence of the flow stress is described for a…

Pattern Formation and Solitons · Physics 2007-05-23 B. V. Petukhov

The Landau Zener method allows to measure very small tunnel splittings \Delta in molecular clusters Fe_8. The observed oscillations of \Delta as a function of the magnetic field applied along the hard anisotropy axis are explained in terms…

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

We study theoretically spin relaxation during phonon-assisted tunneling of a single electron in self-assembled InAs/GaAs quantum-dot molecules formed by vertically stacked dots. We find that the spin-flip tunneling rate may be as high as 1%…

Mesoscale and Nanoscale Physics · Physics 2021-06-23 Michał Gawełczyk , Krzysztof Gawarecki

We show that the nuclear spin dynamics in the single-molecule magnet Mn12-ac below 1 K is governed by quantum tunneling fluctuations of the cluster spins, combined with intercluster nuclear spin diffusion. We also obtain the first…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Andrea Morello , Oleg N. Bakharev , Hans B. Brom , Roberta Sessoli , L. Jos de Jongh

Structural and physical properties determined by measurements on large single crystals of the anisotropic ferromagnet MnBi are reported. The findings support the importance of magneto-elastic effects in this material. X-ray diffraction…

Materials Science · Physics 2014-11-19 Michael A. McGuire , Huibo Cao , Bryan C. Chakoumakos , Brian C. Sales

We report synthesis, structural characterization, and magnetic measurements of amorphous Mn$_{12}$-acetate ribbons with a triclinic short-range crystal order not previously seen in experiment. The ribbons exhibit the same structure of…

Mesoscale and Nanoscale Physics · Physics 2015-11-02 I. Imaz , J. Espin , D. Maspoch , J. Tejada , R. Zarzuela , N. Statuto , E. M. Chudnovsky

We present a theory that elucidates the major momentum and spin relaxation processes for electrons, holes and hot excitons in monolayer transition-metal dichalcogenides. We expand on spin flips induced by flexural phonons and show that the…

Mesoscale and Nanoscale Physics · Physics 2013-09-30 Yang Song , Hanan Dery

In a recent letter Alonso et al. (Phys. Rev. Lett. 87, 097205 (2001)) present Monte Carlo simulations for interacting dipoles. Short-time relaxation was caused by a simple noise field, acting uniformly over an "energy window" of small width…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 P. C. E. Stamp , I. S. Tupitsyn

Ramsey et al. [Nature Phys. 4, 277-281 (2008)] report the observation of quantum interference associated with tunnelling trajectories between states of different total spin length in a dimeric molecular nanomagnet. They argue that the…

Mesoscale and Nanoscale Physics · Physics 2008-07-07 W. Wernsdorfer

It is a common perception that the transport of a spin current in polycrystalline metal is isotropic and independent of the polarization direction, even though spin current is a tensorlike quantity and its polarization direction is a key…

Mesoscale and Nanoscale Physics · Physics 2017-09-22 Chao Zhou , Fatih Kandaz , Yunjiao Cai , Chuan Qin , Mengwen Jia , Zhe Yuan , Yizheng Wu , Yi Ji

We demonstrate that transport spectroscopy of single molecular magnets shows signatures of quantum tunneling at low temperatures. We find current and noise oscillations as function of bias voltage due to a weak violation of spin selection…

Strongly Correlated Electrons · Physics 2009-11-11 C. Romeike , M. R. Wegewijs , H. Schoeller

We report controlled ignition of magnetization reversal avalanches by surface acoustic waves in a single crystal of Mn12 acetate. Our data show that the speed of the avalanche exhibits maxima on the magnetic field at the tunneling…

Other Condensed Matter · Physics 2009-11-11 A. Hernandez-Minguez , J. M. Hernandez , F. MaciaA. Garcia-Santiago , J. Tejada , P. V. Santos

We present a detailed investigation of the temperature and frequency dependence of the anomalous EPR transitions first observed in Mn12-acetate by Hill et al. [Phys. Rev. Lett. 80, 2453 (1998)]. The most dominant of these transitions…

Materials Science · Physics 2007-05-23 R. S. Edwards , S. Hill , S. Maccagnano , J. M. North , N. S. Dalal

We consider transport through a single-molecule magnet strongly coupled to metallic electrodes. We demonstrate that for half-integer spin of the molecule electron- and spin-tunneling \emph{cooperate} to produce both quantum tunneling of the…

Strongly Correlated Electrons · Physics 2009-11-11 C. Romeike , M. R. Wegewijs , W. Hofstetter , H. Schoeller

Quantum transport and spintronics regimes are studied in p- and n-doped atomic layers of hexagonal transition metal dichalcogenides (TMDCs), subject to the interplay between the valley structure and spin-orbit coupling. We find how spin…

Mesoscale and Nanoscale Physics · Physics 2014-12-23 Hector Ochoa , Francesca Finocchiaro , Francisco Guinea , Vladimir I. Fal'ko