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The low energy excitation spectrum of a two-dimensional ferromagnetic material is dominated by single-magnon excitations that show a gapless parabolic dispersion relation with the spin wave vector. This occurs as long as magnetic anisotropy…

Mesoscale and Nanoscale Physics · Physics 2023-10-25 F. Delgado , M. M. Otrokov , A. Arnau

CrI$_{3}$ is considered to be a promising candidate for spintronic devices and data storage. We derived the Heisenberg Hamiltonian for CrI$_{3}$ from density functional calculations using the Liechtenstein formula. Moreover, the…

Materials Science · Physics 2023-04-24 Hung Ba Tran , Hiroyoshi Momida , Yu-ichiro Matsushita , Koun Shirai , Tamio Oguchi

We explore the physics of the anisotropic compass model under the influence of perturbing Heisenberg interactions and present the phase diagram with multiple quantum phase transitions. The macroscopic ground state degeneracy of the compass…

Strongly Correlated Electrons · Physics 2015-05-18 Fabien Trousselet , Andrzej M. Oles , Peter Horsch

Numerical integration of a stochastic Landau-Lifshitz-Gilbert equation is used to study dynamic processes in single-domain nanoscale magnets at nonzero temperatures. Special attention is given to including thermal fluctuations as a Langevin…

Materials Science · Physics 2009-10-31 Gregory Brown , M. A. Novotny , Per Arne Rikvold

Motivated by theoretical and experimental studies reported by Yamaguchi et al. (Phys. Rev. B 98, 094402 (2018)), we performed a cluster mean-field analysis of an anisotropic Heisenberg model with six competing exchange interactions. We…

Strongly Correlated Electrons · Physics 2025-07-04 L. M. Ramos , F. M. Zimmer , M. Schmidt

Motivated by recent experiments reporting superconductivity only at very low temperature in a class of heavy fermion compounds, we study the impact of energy fluctuations with small momentum transfer on the pairing instability near an…

Superconductivity · Physics 2018-12-31 Jian Kang , Rafael M. Fernandes , Elihu Abrahams , Peter Wölfle

We revisit the theory of magnetoresistance for a system of nanoscopic magnetic granules in metallic matrix. Using a simple model for the spin dependent perturbation potential of the granules, we solve Boltzmann equation for the spin…

Materials Science · Physics 2007-05-23 J. Viana Lopes , J. M. B. Lopes dos Santos , Yu. G. Pogorelov

We derive four reduced two-dimensional models that describe, at different spatial scales, the micromagnetics of ultrathin ferromagnetic materials of finite spatial extent featuring perpendicular magnetic anisotropy and interfacial…

Analysis of PDEs · Mathematics 2024-09-12 G. Di Fratta , C. B. Muratov , V. V. Slastikov

We present a systematic 57Fe-Moessbauer study on highly diluted Fe centers in Li2(Li1-xFex)N single-crystals as a function of temperature and magnetic field applied transverse and longitudinal with respect to the single-ion anisotropy axis.…

Strongly Correlated Electrons · Physics 2020-08-26 S. A. Braeuninger , A. Jesche , S. Kamusella , F. Seewald , M. Fix , R. Sarkar , A. A. Zvyagin , H. -H. Klauss

The bias driven perpendicular magnetic anisotropy is a magneto-electric effect that can realize 90$^\circ$ magnetization rotation and even 180$% ^\circ $ flip along the easy axis in the ferromagnets with a minimal energy consumption. This…

Mesoscale and Nanoscale Physics · Physics 2017-03-08 Yuriy G. Semenov , Xi-Lai Li , Ki Wook Kim

Using quantum mechanical perturbation theory (PT) we analyze how the energy of perturbation of different orders is renormalized in solids. We test the validity of PT analysis by considering a specific case of spin-orbit coupling as a…

Materials Science · Physics 2014-07-11 Vladimir Antropov , Liqin Ke , Daniel Åberg

The magnetocrystalline anisotropy energy $E_{anis}$ for a monolayer of Fe and Ni is determined using a fully convergent tight-binding calculation including $s$-$d$ hybridization. The spin-orbit interaction $\lambda_{so}$ is treated…

Condensed Matter · Physics 2016-08-31 T. H. Moos , W. Hübner , K. H. Bennemann

We investigate the far-from-equilibrium nature of magnetic anisotropy and exchange interactions between molecular magnets embedded in a tunnel junction. By mapping to an effective spin model, these magnetic interactions can be divided into…

Mesoscale and Nanoscale Physics · Physics 2015-01-08 Jonas Fransson , Jie Ren , Jian-Xin Zhu

A magnetoelectric effect according to Katsura-Nagaosa-Balatsky mechanism in spin-1/2 $XY$ chain in transverse magnetic field is considered. A spatial orientation of the electric field is chosen to provide an exact solution of the model in…

Strongly Correlated Electrons · Physics 2021-01-19 V. Ohanyan

Recently observed scaling in the random-anisotropy model of amorphous or sintered ferromagnets is derived by an alternative method and extended for studying the dynamical properties in terms of the Landau-Lifshitz equations for spin blocks.…

Disordered Systems and Neural Networks · Physics 2025-02-14 Dmitry A. Garanin , Eugene M. Chudnovsky

31^P NMR spectral features in polycrystalline SmCoPO reveal an axially symmetric local magnetic field. At low temperature, the anisotropy of the internal magnetic field increases rapidly, with K_ab increasing faster than that of K_c. The…

Strongly Correlated Electrons · Physics 2015-05-30 Mayukh Majumder , K. Ghoshray , A. Ghoshray , Anand Pal , V. P. S. Awana

Magnetic anisotropy plays an essential role in information technology applications of magnetic materials, providing a means to retain the long-term stability of a magnetic state in the presence of thermal fluctuations. Anisotropy consists…

Materials Science · Physics 2020-08-05 Richard F. L. Evans , Levente Rózsa , Sarah Jenkins , Unai Atxitia

The effect of surface anisotropy on the distribution of energy barriers in magnetic fine particles of nanometer size is discussed within the framework of the $T\ln(t/\tau_0)$ scaling approach. The comparison between the distributions of the…

We consider the central spin model in the box approximation taking into account external magnetic field and anisotropy of the hyperfine interaction. From the exact Hamiltonian diagonalization we obtain analytical expressions for the nuclear…

Mesoscale and Nanoscale Physics · Physics 2021-11-17 A. V. Shumilin , D. S. Smirnov

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