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Related papers: Subnanosecond Fluctuations in Low-Barrier Nanomagn…

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Each single domain nano-magnet acts as a magnetic dipole in addition it oscillates its magnetization about the easy axis and rotates coherently depending upon temperature and anisotropy. In an ensemble of nano-magnets, the relaxation time…

Mesoscale and Nanoscale Physics · Physics 2013-02-04 Nilangshu K. Das , P. Barat

We revisit the problem of inelastic times governing the temperature behavior of the weak localization correction and mesoscopic fluctuations in one- and two-dimensional systems. It is shown that, for dephasing by the electron electron…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 I. L. Aleiner , Ya. M. Blanter

We consider a reversal of the magnetic moment of a nano-magnet by the fluctuating spin-torque induced by a non-equilibrium current of electron spins. This is an example of the problem of the escape of a particle from a metastable state…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Yasuhiro Utsumi , Tomohiro Taniguchi

We calculate the mesoscopic fluctuations of the magnetic anisotropy of ferromagnetic nanoparticles. A microscopic spin-orbit Hamiltonian considered as a perturbation of the much stronger exchange interaction first yields an explicit…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Gonzalo Usaj , Harold U. Baranger

The exploration of the rich dynamics of electrons is a frontier in fundamental nano-physics. The dynamical behavior of electrons is dominated by random and chaotic thermal motion with ultrafast ($\approx$ ps) and nanoscale scatterings. This…

Mesoscale and Nanoscale Physics · Physics 2021-08-11 Ruijie Qian , S. T. Chui , Zhenghua An , y Hongtao Xu , Zhifang Lin , Zian Ji , Wei Lu

We present a two-current-pulse temporal correlation experiment to study the intrinsic subnanosecond nonequilibrium magnetic dynamics of a nanomagnet during and following a pulse excitation. This method is applied to a model spin-transfer…

Mesoscale and Nanoscale Physics · Physics 2012-06-25 H. Liu , D. Bedau , J. Z. Sun , S. Mangin , E. E. Fullerton , J. A. Katine , A. D. Kent

The dynamics of a spin torque driven ferrimagnetic (FiM) system is investigated using the two-sublattice macrospin model. We demonstrate an ultrafast switching in the picosecond range. However, we find that the excessive current leads to…

Mesoscale and Nanoscale Physics · Physics 2023-04-19 Zhengping Yuan , Jingwei Long , Zhengde Xu , Yue Xin , Lihua An , Jie Ren , Xue Zhang , Yumeng Yang , Zhifeng Zhu

Taking advantage of the anomalous Hall effect, we electrically probe low-frequency magnetization fluctuations at room temperature in a thin ferromagnetic Pt/Co/AlO$_x$ layer stack with perpendicular magnetic anisotropy. We observe a strong…

Mesoscale and Nanoscale Physics · Physics 2024-02-29 Nadine Nabben , Giacomo Sala , Ulrich Nowak , Matthias Krüger , Sebastian T. B. Goennenwein

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

Context. Solar activity cycles vary in amplitude and duration. The variations can be at least partly explained by fluctuations in dynamo parameters. Aims. We want to restrict uncertainty in fluctuating dynamo parameters and find out which…

Solar and Stellar Astrophysics · Physics 2018-07-18 L. L. Kitchatinov , A. V. Mordvinov , A. A. Nepomnyashchikh

The effect of fluctuations on the nuclear magnetic resonance (NMR) relaxation rate, $W$, is studied in a complete phase diagram of a 2D superconductor above the upper critical field line $H_{c2}(T)$ . In the region of relatively high…

Superconductivity · Physics 2015-09-02 Andreas Glatz , Alexey Galda , Andrey A. Varlamov

Atomically thin sheets, such as graphene, are widely used in nanotechnology. Recently they have also been used in applications including kirigami and self-folding origami, where it becomes important to understand how they respond to…

Statistical Mechanics · Physics 2022-09-21 Mohamed El Hedi Bahri , Siddhartha Sarkar , Andrej Košmrlj

We study the spatio-temporal behavior of the Els\"asser variables describing magnetic and velocity field fluctuations, using direct numerical simulations of three-dimensional magnetohydrodynamic turbulence. We consider cases with relatively…

In discrete energy structure of nanoscale magnets, nonadiabatic transitions at avoided level crossings lead to fundamental processes of dynamics of magnetizations. The thermal environment causes dissipative effects on these processes. In…

Materials Science · Physics 2007-05-23 Seiji Miyashita , Keiji Saito , Hiroto Kobayashi , Hans De Raedt

A single-molecule magnet placed in a magnetic field perpendicular to its anisotropy axis can be truncated to an effective two-level system, with easily tunable energy splitting. The quantum coherence of the molecular spin is largely…

Mesoscale and Nanoscale Physics · Physics 2015-06-17 A. Morello , A. Millán , L. J. de Jongh

We study the influence of thermal fluctuations on the magnetic behavior of square mesoscopic superconductors. The strength of thermal fluctuations are parameterized using the Ginzburg number, which is small ($G_i \approx 10^{-10}$) in…

Superconductivity · Physics 2009-11-11 Alexander D. Hernandez , B. J. Baelus , Daniel Dominguez , F. M. Peeters

We present a numerical and theoretical study that supports and explains recent experimental results on anomalous magnetization fluctuations of a uniaxial ferromagnetic film in its low-temperature phase, which is forced by an oscillating…

Materials Science · Physics 2017-10-18 Gloria M. Buendia , Per Arne Rikvold

This work presents 75As NMR spin echo decay rate (1/T2) measurements in Ba(Fe1-xRhx)2As2 superconductors, for 0.041 < x < 0.094. It is shown that 1/T2 increases upon cooling, in the normal phase, suggesting the onset of an unconventional…

Superconductivity · Physics 2013-10-03 L. Bossoni , P. Carretta , W. P. Halperin , S. Oh , A. Reyes , P. Kuhns , P. C. Canfield

Magnetization reversal in magnetic nanostructures is investigated numerically over time-scales ranging from fast switching processes on a picosecond scale to thermally activated reversal on a microsecond time-scale. A simulation of the…

Statistical Mechanics · Physics 2015-06-24 D. Hinzke , U. Nowak

Laser induced modulation of the magnetization dynamics occurring over various time-scales have been unified here for a Ni80Fe20 thin film excited by amplified femtosecond laser pulses. The weak correlation between demagnetization time and…

Mesoscale and Nanoscale Physics · Physics 2018-12-21 Sucheta Mondal , Anjan Barman