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The magnetic phase diagram at zero external field of an ensemble of dipoles with uniaxial anisotropy on a FCC lattice is investigated from tempered Monte Carlo simulations. The uniaxial anisotropy is characterized by a random distribution…

Materials Science · Physics 2020-11-11 V. Russier , Juan J. Alonso , I. Lisiecki , A. T. Ngo , C. Salzemann , S. Nakamae , C. Raepsaet

We present some exact results for the effect of disorder on the critical properties of an anisotropic XY spin chain in a transverse field. The continuum limit of the corresponding fermion model is taken and in various cases results in a…

Disordered Systems and Neural Networks · Physics 2009-10-31 J. E. Bunder , Ross H. McKenzie

We investigate a quantum Heisenberg model with both antiferromagnetic and disordered nearest-neighbor couplings. We use an extended dynamical mean-field approach, which reduces the lattice problem to a self-consistent local impurity problem…

Disordered Systems and Neural Networks · Physics 2009-11-13 S. Burdin , D. R. Grempel , M. Grilli

It is of common knowledge that the direction of easy axis in the finite-size ferromagnetic sample is controlled by its shape. In the present paper we show that a similar phenomenon should be observed in the compensated antiferromagnets with…

Statistical Mechanics · Physics 2010-03-16 Helen V. Gomonay , Vadim M. Loktev

In the search for rare-earth free permanent magnets, various ideas related to shape anisotropy are being pursued. In this work we assess the limits of shape contributions to the reversal stability using micromagnetic simulations. In a first…

Materials Science · Physics 2016-03-30 Simon Bance , Johann Fischbacher , Thomas Schrefl , Inga Zins , Gotthard Rieger , Caroline Cassignol

Numerical simulations by means of the Monte Carlo method have been performed to study the electrical properties of a two-dimensional composite filled with rodlike particles. The main goal was to study the effect of the alignment of such…

We perform a finite size scaling study of the three-dimensional Heisenberg spin glass in the presence of weak random anisotropic interactions, up to sizes L=32. Anisotropies have a major impact on the phase transition. The chiral-glass…

Disordered Systems and Neural Networks · Physics 2015-03-17 V. Martin-Mayor , S. Perez-Gaviro

We consider an effect of a strong magnetic field on the ground state and macroscopic coherent tunneling in small antiferromagnetic particles with uniaxial and biaxial single-ion anisotropy. We find several tunneling regimes that depend on…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 B. A. Ivanov , V. E. Kireev

Here we present a new perspective to the breakdown of ferromagnetic order in two-dimensional spin-lattice models employing the rotation of the underlying lattice. Using an Ising spin system on a square lattice as a prototype, we demonstrate…

Statistical Mechanics · Physics 2021-08-17 Claudio J DaSilva , L. S. Ferreira , A. A. Caparica

Monte Carlo techniques are used to investigate the equilibrium threshold concentration, xe, in the dilute anisotropic antiferromagnet Fe(x)Zn(1-x)F2 in an applied magnetic field, considered to be an ideal random-field Ising model system.…

Disordered Systems and Neural Networks · Physics 2009-10-31 W. C. Barber , D. P. Belanger

We study a relativistic two-dimensional free electron gas in the presence of a uniform external magnetic field and a random static scalar potential. We compute the expectation values of the charge density and the conductivity tensor,…

High Energy Physics - Theory · Physics 2008-02-03 N. Bralic , R. M. Cavalcanti , C. A. A. de Carvalho , P. Donatis

In this article we prove that a classical $XY$ model subjected to weak i.i.d. random field pointing in a fixed direction exhibits residual magnetic order in $\mathbb{Z}^2$ and aligns perpendicular to the random field direction. The paper is…

Probability · Mathematics 2023-06-30 Nicolas Crawford , Wioletta M. Ruszel

The three-dimensional frustrated anisotropic XY model with point disorder is studied with both Monte Carlo simulations and resistively-shunted-junction dynamics to model the dynamics of a type-II superconductor with quenched point pinning…

Superconductivity · Physics 2013-05-29 Peter Olsson

The square lattice spin-1/2 antiferromagnet containing a dilute concentration, $\delta$, of randomly placed ferromagnetic nearest-neighbor bonds is studied at low-temperature via non-linear $\sigma$-model techniques and by exact…

Condensed Matter · Physics 2009-10-22 J. P. Rodriguez , J. Bonca , J. Ferrer

Effects of randomness on the spin-1/2 and 1 antiferromagnetic Heisenberg chains are studied using the quantum Monte Carlo method with the continuous-time loop algorithm. We precisely calculated the uniform susceptibility, string order…

Disordered Systems and Neural Networks · Physics 2007-05-23 Synge Todo , Kiyoshi Kato , Hajime Takayama

We investigate an electromagnetic instability in two-dimensional materials arising from an anisotropy of the Fermi surface, utilizing a kinetic model accounting for the effects of the values of temperature, chemical potential and anisotropy…

Materials Science · Physics 2025-06-27 Diogo Simões , Hugo Terças , Jorge Ferreira

Macroscopic systems with continuous symmetries subjected to oscillatory fields have phases and transitions that are qualitatively different from their equilibrium ones. Depending on the amplitude and frequency of the fields applied,…

Statistical Mechanics · Physics 2009-11-07 I. Junier , J. Kurchan

We present a dynamical mean-field study of antiferromagnetic magnons in one-, two- and three-orbital Hubbard model of square and bcc cubic lattice at intermediate coupling strength. Weinvestigate the effect of anisotropy introduced by an…

Strongly Correlated Electrons · Physics 2021-09-10 A. Niyazi , D. Geffroy , J. Kunes

The crystalline ferromagnet with dipole-dipole interactions is studied within the framework of the three-dimensional random-field Ising model. The field distribution function and the analytic expression for temperature dependent free energy…

Condensed Matter · Physics 2007-05-23 L. L. Afremov , A. V. Panov

The dynamical responses of XY ferromagnet driven by linearly polarised propagating and standing magnetic field wave have been studied by Monte Carlo simulation in three dimensions. In the case of propagating magnetic field wave (with…

Statistical Mechanics · Physics 2018-08-24 Muktish Acharyya
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