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Related papers: Non-equilibrium magnetic fields in ab initio spin …

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We investigate the off-equilibrium dynamics of a spin system with O($N$) symmetry in $2 < d < 4$ spatial dimensions arising by the presence of a slowly varying time-dependent magnetic field $h(t,t_s) \sim t/t_s$, $t_s$ is a time scale, at…

Statistical Mechanics · Physics 2019-01-25 Stefano Scopa

We derive the spin-wave dynamics of a magnetic material from the time-dependent spin density functional theory in the linear response regime. The equation of motion for the magnetization includes, besides the static spin stiffness, a "Berry…

Materials Science · Physics 2009-11-07 Zhixin Qian , Giovanni Vignale

A comparative study of the non-equilibrium magnetic phenomena (magnetic blocking, memory, exchange bias and aging effect) has been presented for ferrimagnetic Co$_{1.75}$Fe$_{1.25}$O$_4$ (CFO) and its composite with non-magnetic BaTiO$_3$…

Materials Science · Physics 2021-05-19 R. N. Bhowmik , R. Ranganathan

Irradiating solids with ultrashort laser pulses is known to initiate femtosecond timescale magnetization dynamics. However, sub-femtosecond spin dynamics have not yet been observed or predicted. Here, we explore ultrafast light-driven spin…

Mesoscale and Nanoscale Physics · Physics 2023-03-28 Ofer Neufeld , Nicolas Tancogne-Dejean , Umberto De Giovannini , Hannes Hübener , Angel Rubio

When a laser pulse excites a ferromagnet, its spin undergoes a dramatic change. The initial demagnetization process is very fast. Experimentally, it is found that the demagnetization time is related to the spin moment in the sample. In this…

Materials Science · Physics 2016-11-11 G. P. Zhang , M. S. Si , Thomas F. George

Processes with oppositely charged spinor particles in initial and/or final states in homogeneous magnetic field B are subject to focusing effects in their relative motion, which yield the amplifying factors in probabilities growing as $eB$.…

High Energy Physics - Phenomenology · Physics 2015-05-14 Yu. A. Simonov

The dynamics of relativistic spinning particles in strong external electromagnetic or gravitational fields is discussed. Spin-orbit coupling is shown to affect such relativistic phenomena as time-dilation and perihelion shift. Possible…

High Energy Physics - Theory · Physics 2023-12-12 J. W. van Holten

We discuss the problem of equilibrium spin currents in ferromagnets with inhomogeneous magnetization. Using simple microscopic models we explain the physical origin of equilibrium spin currents. Next we derive the equilibrium spin current…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Patrick Bruno , Vitalii K. Dugaev

The ultrafast response to an optical pulse excitation of the spin-spin exchange interaction in transition metal anti-ferromagnets is studied within the framework of the time-dependent spin-density functional theory. We propose a formulation…

Mesoscale and Nanoscale Physics · Physics 2017-08-16 Jacopo Simoni , Maria Stamenova , Stefano Sanvito

Recent experimental results have pushed the limits of magnetization dynamics to pico- and femtosecond timescales. This ultra-fast spin dynamics occurs in extreme conditions of strong and rapidly varying fields and high temperatures. This…

Materials Science · Physics 2009-11-13 U. Atxitia , O. Chubykalo-Fesenko , R. W. Chantrell , U. Nowak , A Rebei

Exciting a ferromagnetic sample with an ultrashort laser pulse leads to a quenching of the magne- tization on a subpicosecond timescale. On the basis of the equilibration of intensive thermodynamic variables we establish a powerful model to…

Materials Science · Physics 2014-10-22 B. Y. Mueller , B. Rethfeld

Here we consider the magnetization dynamics in ferromagnetic nanoparticles or films driven by external magnetic field pulses directed transverse to the initial equilibrium state. The excitation pulse drives large-angle ultra-fast…

Dynamical Systems · Mathematics 2024-10-23 Alessandro Fortunati , Massimiliano d'Aquino , Claudio Serpico

Highly intense electric field pulses can move the electronic momentum occupation in correlated metals over large portions of the Brillouin zone, leading to phenomena such as dynamic Bloch oscillations. Using the non-equilibrium…

Strongly Correlated Electrons · Physics 2020-04-14 Nagamalleswararao Dasari , Martin Eckstein

It is shown that the electric current of massive fermions along the external magnetic field can be excited in the case when particles possess anomalous magnetic moments and electroweakly interact with background matter. This current is…

High Energy Physics - Phenomenology · Physics 2018-02-15 Maxim Dvornikov

Temperature-dependent magnetic experiments like pump-probe measurements generated by a pulsed laser have become a crucial technique for switching the magnetization in the picosecond time scale. Apart from having practical implications on…

Magnetization reversal in permanent magnets occurs by the nucleation and expansion of reversed domains. Micromagnetic theory offers the possibility to localize the spots within the complex structure of the magnet where magnetization…

Materials Science · Physics 2018-05-25 J. Fischbacher , A. Kovacs , L. Exl J. Kühnel , E. Mehofer , H. Sepehri-Amin , T. Ohkubo , K. Hono , T. Schrefl

We studied the dynamics of the so-called $\theta$-term, which exists in topological materials and is related to a hypothetical field predicted by Peccei-Quinn in particle physics, in a magnetic superlattice constructed using a topological…

Mesoscale and Nanoscale Physics · Physics 2018-06-13 Katsuhisa Taguchi , Tatsushi Imaeda , Tetsuya Hajiri , Takuya Shiraishi , Yukio Tanaka , Naoya Kitajima , Tatsuhiro Naka

The generation of large-scale magnetic fields ($\overline{\mathbf{B}}$) in astrophysical systems is driven by the mean turbulent electromotive force ($\overline{{\cal E}}$), the cross correlation between local fluctuations of velocity and…

Astrophysics of Galaxies · Physics 2022-02-16 Abhijit B. Bendre , Kandaswamy Subramanian

Ultrafast laser excitation of ferromagnetic metals gives rise to correlated, highly non-equilibrium dynamics of electrons, spins and lattice, which are, however, poorly described by the widely-used three-temperature model (3TM). Here, we…

Materials Science · Physics 2024-01-17 Markus Weißenhofer , Peter M. Oppeneer

The dynamics of magnetization in the presence of spin-transfer torque was studied. We derived the equation for the motion of magnetization in the presence of a spin current by using the local equilibrium assumption in non-equilibrium…

Mesoscale and Nanoscale Physics · Physics 2008-08-07 Kazuhiko Seki , Hiroshi Imamura