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Related papers: Thermal activation in permanent magnets

200 papers

We propose an adiabatic magnetization process for cooling the Fermi electron gas to ultra-low temperatures as an alternative to the known adiabatic demagnetization mechanism. We show via a new adiabatic equation that at the constant density…

Plasma Physics · Physics 2019-04-03 Nodar L. Tsintsadze , Levan N. Tsintsadze

Uniaxially (Z-axis) anisotropic Heisenberg ferromagnet, in presence of time dependent (but uniform over space) magnetic field, is studied by Monte Carlo simulation. The time dependent magnetic field was taken as elliptically polarised where…

Statistical Mechanics · Physics 2011-01-21 Muktish Acharyya

The QCD phase diagram in the temperature versus quark chemical potential plane is studied in the presence of a magnetic field, using the linear sigma model coupled to quarks. It is shown that the decrease of the couplings with increasing…

High Energy Physics - Phenomenology · Physics 2015-12-02 Alejandro Ayala , C. A. Dominguez , L. A. Hernandez , M. Loewe , R. Zamora

We investigate the quantum evolution of spin states of a single molecular magnet in a local electric field. The decoherence of a $\texttt{\{}\emph{Cu}_3\texttt{\}}$ single molecular magnet weakly coupled to a thermal bosonic environment can…

Quantum Physics · Physics 2015-06-18 Xiang Hao , Xiaoqun Wang , Chen Liu , Shiqun Zhu

We examine the entanglement of thermal states of n spins interacting through different types of XY couplings in the presence of a magnetic field, by evaluating the negativities of all possible bipartite partitions of the whole system and of…

Quantum Physics · Physics 2015-06-18 R. Rossignoli , N. Canosa

We developed a new technique for measuring the thermodynamic entropy as a function of the magnetic field angle. This technique enables high-resolution angle-resolved measurements of the entropy in an unprecedentedly short measuring time.…

Strongly Correlated Electrons · Physics 2018-06-15 Shunichiro Kittaka , Shota Nakamura , Hiroaki Kadowaki , Hiroshi Takatsu , Toshiro Sakakibara

It is known that in the 2+1 dimensional quantum electrodynamics with Chern-Simons term, spontaneous magnetic field induces Lorentz symmetry breaking. In this paper, thermodynamical characters, especially the phase structure of this model…

High Energy Physics - Theory · Physics 2009-09-25 Shinya Kanemura , Takao Matsushita

A model is studied for the theoretical description of nanoscale magnetic films with high perpendicular anisotropy. In the model the magnetic film is described in terms of single domain magnetic grains with Ising-like behavior, interacting…

Statistical Mechanics · Physics 2016-08-31 U. Nowak

The mechanisms of thermally activated magnetization switching in small ferromagnetic particles driven by an external magnetic field are investigated. For low uniaxial anisotropy the spins rotate coherently while for sufficiently large…

Statistical Mechanics · Physics 2009-10-31 U. Nowak , D. Hinzke

The thermal activation of magnetization reversal in magnetic nanoparticles is controlled by the anisotropy-energy barrier. Using perturbation theory, exact diagonalization and stability analysis of the ferromagnetic spin-s Heisenberg model…

Mesoscale and Nanoscale Physics · Physics 2012-04-16 Mohammad Sayad , Daniel Gütersloh , Michael Potthoff

We investigate the structural, magnetocrystalline anisotropy, critical behaviour, and magnetocaloric effect in the layered room-temperature monoclinic ferromagnet Cr$_{1.38}$Te$_2$. The critical behavior is studied by employing various…

Numerical solutions of the Landau-Lifshitz-Gilbert micromagnetic model incorporating thermal fluctuations and dipole-dipole interactions (calculated by the Fast Multipole Method) are presented for systems composed of nanoscale iron pillars…

Materials Science · Physics 2009-11-07 Gregory Brown , M. A. Novotny , Per Arne Rikvold

We study the magnetization dynamics in nanomagnets excited by stochastic magnetic fields to mimic temperature in a micromagnetic framework. The effect of confinement arising from the finite size of the structures is investigated, and we…

Mesoscale and Nanoscale Physics · Physics 2021-04-09 Samuel D. Slöetjes , Björgvin Hjörvarsson , Vassilios Kapaklis

It has been shown that a single-domain magnetic nanoparticle can be effectively switched by a linear down-chirp microwave field pulse (DCMWP) in zero temperature limit. However, finite temperature is ubiquitous in practice. Here, we study…

Mesoscale and Nanoscale Physics · Physics 2021-06-21 M. T. Islam , M. A. J. Pikul , X. S. Wang

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

We consider the influence of interparticle interaction on the magnetization reversal in the oriented Stoner-Wohlfarth nanoparticles ensemble. To do so, we solve a kinetic equation for the relaxation of the overall ensemble magnetization to…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 A. A. Timopheev , S. M. Ryabchenko , V. M. Kalita , A. F. Lozenko , P. A. Trotsenko , V. A. Stephanovich , A. M. Grishin , M. Munakata

The influence of the time variation of the magnetic field, termed the magnetic field profile, on the performance of a magnetocaloric refrigeration device using the active magnetic regeneration (AMR) cycle is studied for a number of process…

Instrumentation and Detectors · Physics 2014-10-24 R. Bjørk , K. Engelbrecht

Thermodynamics of magnetic materials is discussed in practical, lab-oriented terms. In the common experimental configuration in which the external magnetic field comes from a solenoidal coil connected to a power supply, magnetic work is…

Classical Physics · Physics 2007-05-23 Thomas R. Lemberger

We consider quantum Heisenberg ferro- and antiferromagnets on the square lattice with exchange anisotropy of easy-plane or easy-axis type. The thermodynamics and the critical behaviour of the models are studied by the pure-quantum…

Statistical Mechanics · Physics 2015-06-24 A. Cuccoli , T. Roscilde , V. Tognetti , R. Vaia , P. Verrucchi

Recent experimental and theoretical studies show that the switching behavior of magnetic nanoparticles can be well controlled by external time-dependent magnetic fields. In this work, we inspect theoretically the influence of the…

Other Condensed Matter · Physics 2013-09-18 Alexander Sukhov , Jamal Berakdar