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Related papers: Thermal activation in permanent magnets

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The temperature dependence of the response of a magnetic system to an applied field can be understood qualitatively by considering variations in the energy surface characterizing the system and estimated quantitatively with rate theory. In…

Mesoscale and Nanoscale Physics · Physics 2015-12-08 M. Moskalenko , P. F. Bessarab , V. M. Uzdin , Hannes Jónsson

The maximum coercivity that can be achieved for a given hard magnetic alloy is estimated by computing the energy barrier for the nucleation of a reversed domain in an idealized microstructure without any structural defects and without any…

We report a finite temperature micromagnetic method (FTM) that allows for the calculation of the coercive field of arbitrary shaped magnetic nanostructures at time scales of nanoseconds to years. Instead of directly solving the…

Materials Science · Physics 2015-06-03 D. Suess , L. Breth , J. Lee , M. Fuger , C. Vogler , F. Bruckner , B. Bergmair , T. Huber , J. Fidler , T. Schrefl

The development of permanent magnets containing less or no rare-earth elements is linked to profound knowledge of the coercivity mechanism. Prerequisites for a promising permanent magnet material are a high spontaneous magnetization and a…

The Nd permanent magnet (Nd$_{2}$Fe$_{14}$B) is an indispensable material used in modern energy conversion devices. The realization of high coercivity at finite temperatures is a burning issue. One of the important ingredients for…

Materials Science · Physics 2021-01-20 Masamichi Nishino , Ismail Enes Uysal , Seiji Miyashita

We study computational behavior of a mesoscopic model describing temperature/external magnetic field-driven evolution of magnetization. Due to nonconvex anisotropy energy describing magnetic properties of a body, magnetization can develop…

Numerical Analysis · Mathematics 2016-11-22 Martin Kružík , Jan Valdman

Electron heating in an ultracold neutral plasma is modeled using classical molecular dynamics simulations in the presence of an externally applied magnetic field. A sufficiently strong magnetic field is found to reduce disorder induced…

Plasma Physics · Physics 2018-02-14 Sanat Kumar Tiwari , Scott D. Baalrud

We investigate the contributions of finite-temperature magnetic fluctuations to the thermodynamic properties of bcc Fe as a function of pressure. First, we apply a tight-binding total-energy model parameterized to first-principles…

Materials Science · Physics 2010-07-21 Xianwei Sha* , R. E. Cohen

Atomistic spin model simulations are immensely useful in determining temperature dependent magnetic prop- erties, but are known to give the incorrect dependence of the magnetization on temperature compared to exper- iment owing to their…

Mesoscale and Nanoscale Physics · Physics 2015-05-12 R. F. L. Evans , U. Atxitia , R. W. Chantrell

We study symmetry restoration at finite temperature in the theory of a charged scalar field interacting with a constant, external magnetic field. We compute the finite temperature effective potential including the contribution from ring…

High Energy Physics - Phenomenology · Physics 2009-11-10 Alejandro Ayala , Angel Sánchez , Gabriella Piccinelli , Sarira Sahu

We have investigated the magnetocaloric effects in antiferromagnets and compared them with those in ferromagnets using Monte Carlo simulations. In antiferromagnets, the magnetic entropy reaches a maximum value at a finite magnetic field…

Materials Science · Physics 2014-03-20 Ryo Tamura , Takahisa Ohno , Hideaki Kitazawa

Magnetic moment of electron at finite temperature is directly related to the modified electron mass in the background heat bath. Magnetic moment of electron gets modified when it couples with the magnetic field at finite temperature through…

High Energy Physics - Theory · Physics 2015-06-04 Samina S. Masood , Mahnaz Q. Haseeb

A magnetic field was recently shown to enhance field-parallel heat conduction in a strongly correlated plasma whereas cross-field conduction is reduced. Here we show that in such plasmas, the magnetic field has the additional effect of…

Plasma Physics · Physics 2017-01-25 T. Ott , M. Bonitz , P. Hartmann , Z. Donkó

An external magnetic field induces large relative changes in the entropy of one-dimensional quantum spin systems at finite temperatures. This leads to a magnetocaloric effect, i.e. a change in temperature during an adiabatic…

Strongly Correlated Electrons · Physics 2007-05-23 M. E. Zhitomirsky , A. Honecker

Temperature dependent FMR-measurements of Ni and Co films are analysed using a microscopic theory for ultrathin metallic systems. The mechanism governing the temperature dependence of the magnetic anisotropy energy is identified and…

Strongly Correlated Electrons · Physics 2009-11-11 J. Kienert , S. Schwieger , K. Lenz , J. Lindner , K. Baberschke , W. Nolting

We study the mean field dilute model of a ferromagnet. We find and prove an expression for the free energy density at high temperature, and at temperature zero. We find the critical line of the model, separating the phase with zero…

Statistical Mechanics · Physics 2009-11-13 Luca De Sanctis , Francesco Guerra

We studied the temperature dependence of the magnetization reversal in individual submicron permalloy disks with micro-Hall and bend-resistance magnetometry. The nucleation field exhibits a nonmonotonic dependence with positive and negative…

Mesoscale and Nanoscale Physics · Physics 2010-03-17 G. Mihajlovic , M. S. Patrick , J. E. Pearson , V. Novosad , S. D. Bader , M. Field , G. J. Sullivan , A. Hoffmann

The magnetic properties of Cu97Co3 and Cu90Co10 granular alloys were measured over a wide temperature range (2 to 300K). The measurements show an unusual temperature dependence of the coercive field. A generalized model is proposed and…

Materials Science · Physics 2009-11-10 W. C. Nunes , W. S. D. Folly , J. P. Sinnecker , M. A. Novak

We study symmetry restoration at finite temperature in the standard model during the electroweak phase transition in the presence of a weak magnetic field. We compute the finite temperature effective potential up to the contribution of ring…

High Energy Physics - Phenomenology · Physics 2011-01-17 Jorge Navarro , Angel Sanchez , Maria Elena Tejeda-Yeomans , Alejandro Ayala , Gabriella Piccinelli

We report experimental evidence of the effect of an applied magnetic field on the non-thermal magnetic relaxation in a disk-shaped type-I lead superconductor. The time evolution of the irreversible magnetization proves to be logarithmic for…

Superconductivity · Physics 2015-05-28 Saül Vélez , Ricardo Zarzuela , Antoni García-Santiago , Javier Tejada
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