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Related papers: Spin tunneling in magnetic molecules: Quantitative…

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We present a simple model of composite particle tunnelling through a rectangular potential barrier in presence of magnetic field. The exact numerical solution of the problem is provided and the applicability to real physical situations is…

Quantum Physics · Physics 2024-10-22 Bernard Faulend , Jan Dragašević

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

Inspired by a recent paper$^*$ by C. Fefferman, J. Shapiro and M. Weinstein, we investigate quantum tunneling for a Hamiltonian with a symmetric double well and a uniform magnetic field. In the simultaneous limit of strong magnetic field…

Mathematical Physics · Physics 2023-09-06 B. Helffer , A. Kachmar

A scanning tunneling microscope can probe the inelastic spin excitations of a single magnetic atom in a surface via spin-flip assisted tunneling in which transport electrons exchange spin and energy with the atomic spin. If the inelastic…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 F. Delgado , J. Fernández-Rossier

Strong electric fields can be used to align molecules. However, a non-polar molecule such as H$_2$ has no preference for its orientation. There are thus two equivalent configurations with equal energy separated by a potential-energy…

Chemical Physics · Physics 2025-12-02 J. Amira Geuther , Marit R. Fiechter , Jeremy O. Richardson

We prepared magnetic tunnel junctions with one ferromagnetic and one superconducting Al-Si electrode. Pure cobalt electrodes were compared with a Co-Fe-B alloy and the Heusler compound Co2FeAl. The polarization of the tunneling electrons…

Materials Science · Physics 2015-06-03 Oliver Schebaum , Jagadeesh S. Moodera , Andy Thomas

It is shown that a single molecular magnet placed in a rapidly oscillating magnetic field displays the phenomenon of quenching of tunneling processes. The results open a way to manipulate the quantum states of molecular magnets by means of…

Mesoscale and Nanoscale Physics · Physics 2015-12-09 María José Santander , Alvaro S. Nunez , A. Roldán-Molina , Roberto E. Troncoso

Low-temperature magnetization process of the nanoscale iron cluster in linearly sweeped fields is investigated by a numerical analysis of time-dependent Schr$\ddot{\rm o}$dinger equation and the quantum master equation. We introduce an…

Materials Science · Physics 2009-11-07 Hiroki Nakano , Seiji Miyashita

The first X-ray magnetic circular dichroism (XMCD) spectra on the title compounds are presented. In Mn12 the Mn(III) and Mn(IV) contributions are clearly apparent and evidence the opposite spin arrangement of the two ions. For Fe8 the…

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

We derive the quantization of magnetic helicity in the solid-state and demonstrate tunable macroscopic quantum tunneling, coherence, and oscillation for a skyrmion spin texture stabilized in frustrated magnets. We also discuss the parameter…

Mesoscale and Nanoscale Physics · Physics 2022-09-29 Christina Psaroudaki , Christos Panagopoulos

A method to calculate the effective spin Hamiltonian for a transition metal impurity in a non- magnetic insulating host is presented and applied to the paradigmatic case of Fe in MgO. In a first step we calculate the electronic structure…

Mesoscale and Nanoscale Physics · Physics 2015-04-03 Alejandro Ferrón , Fernando Delgado , Joaquín Fernández-Rossier

Understanding the nature of magnetic interactions in ultra-small magnetic ensembles and their intrinsic properties is vital to uncover the dynamics therein. In this study we reveal the spin dynamics of hexagonally arranged Fe atoms on…

Mesoscale and Nanoscale Physics · Physics 2018-08-21 Tamene R. Dasa , Valeri S. Stepanyuk

Fe3Si is a ferromagnetic material with possible applications in magnetic tunnel junctions. When doped with Mn, the material shows a complex magnetic behavior, as suggested by older experiments. We employed the Korringa-Kohn-Rostoker (KKR)…

Materials Science · Physics 2016-08-14 Marjana Ležaić , Phivos Mavropoulos , Stefan Blügel , Hubert Ebert

Magnetic tunnel junctions with wide band gap semiconductor ZnTe barrier were fabricated. A very low barrier height and sizable magnetoresistance were observed in the Fe/ZnTe/Fe junctions at room temperature. The nonlinear I-V characteristic…

Mesoscale and Nanoscale Physics · Physics 2022-11-01 W. G. Wang , C. Ni , A. Ozbay , L. R. Shah , X. Fan , X. M. Kou , E. R. Nowak , J. Q. Xiao

A scanning tunneling microscope (STM) can probe the inelastic spin excitations of single magnetic atoms in a surface via spin-flip assisted tunneling. A particular and intriguing case is the Mn dimer case. We show here that the existing…

Mesoscale and Nanoscale Physics · Physics 2022-08-31 F. Delgado , J. Fernández-Rossier

Metallorganic molecules have been proposed as excellent spin filters in molecular spintronics because of the large spin-polarization of their electronic structure. However, most of the studies involving spin transport, have disregarded…

Mesoscale and Nanoscale Physics · Physics 2015-04-29 P. N. Abufager , R. Robles , N. Lorente

Electron tunneling through mesoscopic metallic grains can be treated perturbatively only provided the tunnel junction conductances are sufficiently small. If it is not the case, fluctuations of the grain charge become strong. As a result…

Condensed Matter · Physics 2009-10-28 D. S. Golubev , A. D. Zaikin

The structural, electronic and magnetic properties of Fe7S8 material have been studied within the framework of the ab-initio calculations, the mean field approximation (MFA) and Monte Carlo simulation (MCS). Our study shows that two forms…

Materials Science · Physics 2020-12-09 S. Benyoussef , Y. EL Amraoui , H. Ez-Zahraouy , D. Mezzane , Z. Kutnjak , I. A. Luk'yanchuk , M. EL Marssi

The problem of electron tunnelling through a symmetric semiconductor barrier based on zinc-blende-structure material is studied. The $k^3$ Dresselhaus terms in the effective Hamiltonian of bulk semiconductor of the barrier are shown to…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 V. I. Perel' , S. A. Tarasenko , I. N. Yassievich , S. D. Ganichev , V. V. Bel'kov , W. Prettl