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The current efforts to fabricate non-volatile magnetic recording media with a high areal density is deteriorated by the increasing temporal instability of the stored information. If the stored energy per magnetic particle competes with the…

Materials Science · Physics 2009-10-31 P. J. Jensen

We investigate in detail the initial susceptibility, magnetization curves, and microstructure of ferrofluids in various concentration and particle dipole moment ranges by means of molecular dynamics simulations. We use the Ewald summation…

Soft Condensed Matter · Physics 2016-08-16 Zuowei Wang , Christian Holm , Hanns Walter Müller

By event-driven molecular dynamics simulations we investigate magneto-transport in a two-dimensional model with randomly distributed scatterers close to the field-induced localization transition. This transition is generated by percolating…

Mesoscale and Nanoscale Physics · Physics 2015-12-14 Walter Schirmacher , Benedikt Fuchs , Felix Höfling , Thomas Franosch

Mobility edge (ME), representing the critical energy that distinguishes between extended and localized states, is a key concept in understanding the transition between extended (metallic) and localized (insulating) states in disordered and…

Disordered Systems and Neural Networks · Physics 2024-05-24 Yaru Liu , Zeqing Wang , Chao Yang , Jianwen Jie , Yucheng Wang

The impact of an external electric field on the spin relaxation in a disordered two-dimensional electron system is studied within the framework of a field-theoretical formulation. Generalized Bloch-equations for the diffusion and the decay…

Disordered Systems and Neural Networks · Physics 2009-11-10 O. Bleibaum

We study slow relaxation processes in the point vortex model for the two-dimensional pure electron plasma under the strong magnetic field. By numerical simulations, it is shown that, from an initial state, the system undergoes the fast…

Statistical Mechanics · Physics 2009-11-11 Ryo Kawahara , Hiizu Nakanishi

Transport of electrons through two-dimensional semiconductor structures on the nanoscale in the presence of perpendicular magnetic field depends on the interplay of geometry of the system, the leads, and the magnetic length. We use a…

Mesoscale and Nanoscale Physics · Physics 2012-03-15 Vidar Gudmundsson , Chi-Shung Tang , Cosmin Mihai Gainar , Valeriu Moldoveanu , Andrei Manolescu

We investigate how external screening shapes excitons in two-dimensional (2d) semiconductors embedded in laterally structured dielectric environments. An atomic scale view of these elementary excitations is developed using models which…

We study the relaxation of interacting single--molecule magnets (SMMs) in both spatially ordered and disordered systems. The tunneling window is assumed to be, as in Fe8, much narrower than the dipolar field spread. We show that relaxation…

Statistical Mechanics · Physics 2007-05-23 J. F. Fernandez , J. J. Alonso

The effect of a spatially modulated magnetic field on the weak localization phenomenon in two-dimensional electron gas (2DEG) is studied. Both the dephasing time $\tau_H$ and magnetoresistance are shown to reveal a nontrivial behavior as…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 A. S. Melnikov , S. V. Mironov , S. V. Sharov

The combined influence of disorder and interactions on the transport properties of electrons in one dimension is investigated. The numerical simulations are carried out by means of the Hartree-Fock-based diagonalization (HFD), a very…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 Michael Schreiber , Frank Epperlein , Thomas Vojta

We investigated the effect of intermolecular dipolar interactions on a cubic 3D ensemble of 5X5X4=100 nanomagnets, each with spin $S = 5$. We employed the Landau-Lifshitz-Gilbert equation to solve for the magnetization $M(B)$ curves for…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Marisol Alcantara Ortigoza , Richard A. Klemm , Talat S. Rahman

Superparamagnetic colloids present interesting assembly dynamics and propulsion in time-varying magnetic fields due to their magnetic relaxation. However, little is known about the mechanisms governing this magnetic relaxation, which is…

A fundamental challenge for disordered solids is predicting macroscopic yield from the microscopic arrangements of constituent particles. Yield is accompanied by a sudden and large increase in energy dissipation due to the onset of plastic…

Soft Condensed Matter · Physics 2022-06-01 K. L. Galloway , E. G. Teich , X-g Ma , Ch. Kammer , I. R. Graham , N. C. Keim , C. Reina , D. J. Jerolmack , A. G. Yodh , P. E. Arratia

Transverse NMR relaxation from spins diffusing through a random magnetic medium is sensitive to its structure on a mesoscopic scale. In particular, this results in the time-dependent relaxation rate. We show analytically and numerically…

Soft Condensed Matter · Physics 2018-10-12 Alexander Ruh , Philipp Emerich , Harald Scherer , Dmitry S. Novikov , Valerij G. Kiselev

The development of new computing technologies has given a new stimulus in the study of multiferroics. The use of multiferroics allows the realization of competitive energy efficient scalable logic and storage devices. The low-power…

Materials Science · Physics 2023-10-10 Z. V. Gareeva , N. V. Shulga , A. K. Zvezdin

A novel strategy is proposed for the coupling of field and circuit equations when modeling power devices in the low-frequency regime. The resulting systems of differential-algebraic equations have a particular geometric structure which…

Numerical Analysis · Mathematics 2024-04-25 Herbert Egger , Idoia Cortes Garcia , Vsevolod Shashkov , Michael Wiesheu

Measurements of the magnetic irreversibility line and time-logarithmic decay of the magnetization are described for three $Fe_{2}O_{3}$ samples composed of regular amorphous, acicular amorphous and crystalline nanoparticles. The relaxation…

Condensed Matter · Physics 2009-10-31 R. Prozorov , Y. Yeshurun , T. Prozorov , A. Gedanken

In this paper, we study the defects effect on magnetic properties of a nano-square structure. This system is composed with alternate layers consisting of the spins {\sigma}=3/2 and S=1. More precisely, we examine the effect of different…

Statistical Mechanics · Physics 2017-07-07 S. Aouini , S. Ziti , H. Labrim , L. Bahmad

Defects intentionally introduced into magnetic materials often have a profound effect on the physical properties. Specifically tailored neutron spectroscopic experiments can provide detailed information on both the local exchange…

Materials Science · Physics 2017-02-28 Albert Furrer
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