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Advanced thermostats for molecular dynamics are proposed on the base of the rigorous Langevin dynamics. Because the latter accounts for the subsystem-bath interactions in details, the bath anisotropy and nonuniformity are described via the…

Statistical Mechanics · Physics 2023-10-03 Roumen Tsekov

A new mechanisms for damping of slow magnetosonic waves (SMW) by pressure induced oscillations of the ionization degree is proposed. An explicit formula for the damping rate is quantitatively derived. Physical conditions where the new…

Plasma Physics · Physics 2020-12-02 Todor M. Mishonov , Albert M. Varonov

We consider various sets of Vlasov-Fokker-Planck equations modeling the dynamics of charged particles in a plasma under the effect of a strong magnetic field. For each of them in a regime where the strength of the magnetic field is…

Analysis of PDEs · Mathematics 2020-06-30 Maxime Herda , Luis Miguel Rodrigues

For systems in equilibrium at a temperature $T$, thermal noise and energy damping are related to $T$ through the fluctuation-dissipation theorem (FDT). We study here an extension of the FDT to an out of equilibrium steady state: a…

Statistical Mechanics · Physics 2023-03-23 Alex Fontana , Ludovic Bellon

Magnetization dynamics are strongly influenced by damping. An effective damping constant {\alpha}eff is often determined experimentally from the spectral linewidth of the free induction decay of the magnetization after the system is excited…

Mesoscale and Nanoscale Physics · Physics 2016-01-20 Amir Capua , See-hun Yang , Timothy Phung , Stuart S. P. Parkin

A well-established numerical technique to study the dynamics of spin systems in which symmetries and conservation laws play an important role is to microcanonically integrate their reversible equations of motion, obtaining thermalization…

Statistical Mechanics · Physics 2023-06-27 Andrea Cavagna , Javier Cristín , Irene Giardina , Mario Veca

The mechanism of Landau damping is observed in various systems from plasma oscillations to accelerators. Despite its widespread use, some confusion has been created, partly because of the different mechanisms producing the damping but also…

Accelerator Physics · Physics 2016-01-21 W. Herr

A numerical model is constructed for modelling macroscale damping effects induced by the first order martensite phase transformations in a shape memory alloy rod. The model is constructed on the basis of the modified Landau-Ginzburg theory…

Computational Engineering, Finance, and Science · Computer Science 2025-10-20 Linxiang X. Wang , Roderick V. N. Melnik

Ferromagnetic resonance in thin films is analyzed under the influence of spatiotemporal feedback effects. The equation of motion for the magnetization dynamics is nonlocal in both space and time and includes isotropic, anisotropic and…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 Thomas Bose , Steffen Trimper

Starting from the Dirac-Kohn-Sham equation we derive the relativistic equation of motion of spin angular momentum in a magnetic solid under an external electromagnetic field. This equation of motion can be written in the form of the…

Materials Science · Physics 2016-10-20 Ritwik Mondal , Marco Berritta , Peter M. Oppeneer

We study the effect of a magnetic field on the thermal relaxation of non-interacting small monodomain particle systems particles with a distribution of anisotropy constants and random easy-axes directions. Numerical calculations of the…

Materials Science · Physics 2007-05-23 Oscar Iglesias , Amilcar Labarta

The dynamics of magnetization near a stable equilibrium in ferromagnetic nanomagnets are examined within the Landau--Lifshitz--Gilbert (LLG) framework. For a small angle precession, the dependence of ferromagnetic resonance (FMR) frequency,…

In analogy to nanoscopic molecules that are composed of individual atoms, we consider an active "microswimmer molecule". It is built up from three individual magnetic colloidal microswimmers that are connected by harmonic springs and…

Soft Condensed Matter · Physics 2016-04-12 Sonja Babel , Hartmut Löwen , Andreas M. Menzel

This article addresses a problem of micromagnetics: the reversal of magnetic moments in layered spring magnets. A one-dimensional model is used of a film consisting of several atomic layers of a soft material on top of several atomic layers…

Dynamical Systems · Mathematics 2025-10-20 J. Samuel Jiang , Hans G. Kaper , Gary K. Leaf

We report device level damping measurements using spin-torque driven ferromagnetic resonance on perpendicular magnetic random-access memory (MRAM) cells. It is shown that thermal agitation enhances the apparent damping for cells smaller…

Mesoscale and Nanoscale Physics · Physics 2024-07-31 H. J. Richter , G. Mihajlović , R. V. Chopdekar , W. Jung , J. Gibbons , N. D. Melendez , M. K. Grobis , T. S. Santos

Magnetization manipulation is becoming an indispensable tool for both basic and applied research. Theory predicts two types of ultrafast demagnetization dynamics classified as type I and type II. In type II materials, a second slower…

Materials Science · Physics 2014-05-08 J. Mendil , P. C. Nieves , O. Chubykalo-Fesenko , J. Walowski , M. Münzenberg , T. Santos , S. Pisana

Turbulence is thought to play a role in the heating of the solar wind plasma, though many questions remain to be solved regarding the exact nature of the mechanisms driving this process in the heliosphere. In particular, the physics of the…

Plasma Physics · Physics 2022-04-04 Sarah A. Horvath , Gregory G. Howes , Andrew J. McCubbin

The interrelation of dynamic processes active on separated time-scales in glasses and viscous liquids is investigated using a model displaying two time-scale bifurcations both between fast and secondary relaxation and between secondary and…

Disordered Systems and Neural Networks · Physics 2015-03-19 Andrea Crisanti , Luca Leuzzi , Matteo Paoluzzi

There is a widely-held belief amongst theoreticians that the Gilbert damping parameter {\alpha} in magnetization dynamics is infinite for a pure metal at T=0. The basic error leading to this belief is pointed out explicitly and the various…

Materials Science · Physics 2018-09-26 D. M. Edwards

A unified model of molecular and atomistic spin dynamics is presented enabling simulations both in microcanonical and canonical ensembles without the necessity of additional phenomenological spin damping. Transfer of energy and angular…