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Related papers: Dipolar induced anisotropy in the random-field Isi…

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We consider the random transverse-field Ising model in $d=3$ dimensions with long-range ferromagnetic interactions which decay as a power $\alpha > d$ with the distance. Using a variant of the strong disorder renormalization group method we…

Statistical Mechanics · Physics 2016-06-08 István A. Kovács , Róbert Juhász , Ferenc Iglói

In this study we calculate the dipole-coupling-induced quartic in-plane anisotropy of a square ferromagnetic Heisenberg monolayer. This anisotropy increases with an increasing temperature, reaching its maximum value close to the Curie…

Strongly Correlated Electrons · Physics 2009-11-07 M. Dantziger , B. Glinsmann , S. Scheffler , B. Zimmermann , P. J. Jensen

We elucidate the itinerant ferromagnetism of a dipolar Fermi gas with a Raman-induced spin-orbit coupling by investigating the exotic phase diagrams at zero and finite temperature. It is revealed that the dipolar interaction along with…

Quantum Gases · Physics 2022-06-15 Xue-Jing Feng , Xing-Dong Zhao , Wu-Ming Liu

The temperature-driven reorientation transition which, up to now, has been studied by use of Heisenberg-type models only, is investigated within an itinerant-electron model. We consider the Hubbard model for a thin fcc(100) film together…

Strongly Correlated Electrons · Physics 2009-10-31 T. Herrmann , M. Potthoff , W. Nolting

We study the critical dynamics of three-dimensional ferromagnets with uniaxial anisotropy by taking into account exchange and dipole-dipole interaction. The dynamic spin correlation functions and the transport coefficients are calculated…

Statistical Mechanics · Physics 2009-10-31 S. Henneberger , E. Frey , P. G. Maier , F. Schwabl , G. M. Kalvius

The spin-1/2 Ising model on a square lattice, with fluctuating bond interactions between nearest neighbors and in the presence of a random magnetic field, is investigated within the framework of the effective field theory based on the use…

Statistical Mechanics · Physics 2013-04-10 Ioannis A. Hadjiagapiou

We present the first correlated-electron theory of metamagnetism in strongly anisotropic antiferromagnets. Quantum-Monte-Carlo techniques are used to calculate the field vs. temperature phase diagram of the infinite-dimensional Hubbard…

Condensed Matter · Physics 2015-06-25 K. Held , M. Ulmke , D. Vollhardt

We study the critical properties of a two--dimensional Ising model with competing ferromagnetic exchange and dipolar interactions, which models an ultra-thin magnetic film with high out--of--plane anisotropy in the monolayer limit. In this…

Statistical Mechanics · Physics 2009-07-09 S. A. Pighin , S. A. Cannas

Mesoscopic samples of polarized dipolar atoms confined in three spatially separated traps conform an extended Bose-Hubbard Hamiltonian in which different quantum phases appear depending on the competition between tunneling, on-site and long…

Quantum Gases · Physics 2016-03-21 A. Gallemí , M. Guilleumas , R. Mayol , A. Sanpera

We exploit magnetostriction in polydisperse ferrofluids in order to generate nonlinear responses, and apply a thermodynamical method to derive the desired nonlinear magnetic susceptibility. For an ideal gas, this method has been…

Soft Condensed Matter · Physics 2009-11-10 J. P. Huang , C. Holm

We propose a spin model with a new kind of ferromagnetic interaction, which may be called {\it ferromagnetic coupling with threshold}. In this model the contribute of a given spin to the total energy has only two possible values and depends…

Condensed Matter · Physics 2009-10-28 Emilio N. M. Cirillo , Sebastiano Stramaglia

A family of multispecies Ising models on generalized regular random graphs is investigated in the thermodynamic limit. The architecture is specified by class-dependent couplings and magnetic fields. We prove that the magnetizations,…

Mathematical Physics · Physics 2024-03-22 Diego Alberici , Pierluigi Contucci , Emanuele Mingione , Filippo Zimmaro

We explore the equilibrium properties of a two-dimensional Ising spin model with short-range exchange and long-range dipolar interactions as a function of the applied magnetic field H. The model is studied through extensive Monte Carlo…

Materials Science · Physics 2010-11-24 Rogelio Diaz-Mendez , Roberto Mulet

We employ density functional theory to study in detail the crystallization of super-paramagnetic particles in two dimensions under the influence of an external magnetic field that lies perpendicular to the confining plane. The field induces…

Soft Condensed Matter · Physics 2009-11-13 Sven van Teeffelen , Hartmut Löwen , Christos N. Likos

All isometrically invariant Markov (strictly local) fields on binary assignments are induced by energy functions that can be represented as linear combinations of area, perimeter, and Euler characteristic. This class of model includes the…

Mathematical Physics · Physics 2026-02-25 Summer Eldridge , Benjamin Schweinhart

We study classical Ising spin-$\frac{1}{2}$ models on the 2D square lattice with ferromagnetic or antiferromagnetic nearest-neighbor interactions, under the effect of a pure imaginary magnetic field. The complex Boltzmann weights of spin…

Statistical Mechanics · Physics 2023-06-27 Roman Krčmár , Andrej Gendiar , Ladislav Šamaj

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

Magnetic anisotropy phenomena in bimetallic antiferromagnets Mn$_2$Au and MnIr are studied by first-principles density functional theory calculations. We find strong and lattice-parameter dependent magnetic anisotropies of the ground state…

We study random close packed systems of magnetic spheres by Monte Carlo simulations in order to estimate their phase diagram. The uniaxial anisotropy of the spheres makes each of them behave as a single Ising dipole along a fixed easy axis.…

Statistical Mechanics · Physics 2019-10-09 J. J. Alonso , B. Alles , V. Russier

We present a detailed study of the magnetic behavior of iron-oxide (gamma-Fe2O3 and Fe3O4) nanoparticles constituents of ferrofluids (FF's) with average particle sizes <d> = 2.5 and 10 nm. The particles were dispersed in the frozen liquid…

Materials Science · Physics 2011-03-24 G. F. Goya , S. L. Gómez , S. M. Shibli