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We propose a microscopic magneto-electric model in which the coupling between spins and electric dipoles is mediated by lattice distortions. The magnetic sector is described by a spin S=1/2 Heisenberg model coupled directly to the lattice…

Strongly Correlated Electrons · Physics 2019-11-06 D. C. Cabra , A. O. Dobry , C. J. Gazza , G. L. Rossini

Vortex rings are remarkably stable structures occurring in numerous systems: for example in turbulent gases, where they are at the origin of weather phenomena [1]; in fluids with implications for biology [2]; in electromagnetic discharges…

The Ginzburg-Landau functional for a two-gap superconductor is derived within the weak-coupling BCS model. The two-gap Ginzburg-Landau theory is, then, applied to investigate various magnetic properties of MgB2 including an upturn…

Superconductivity · Physics 2007-05-23 M. E. Zhitomirsky , V. -H. Dao

Sufficiently thin films of type-I superconductor in a perpendicular magnetic field exhibit a triangular vortex lattice, while thick films develop an intermediate state. To elucidate what happens between these two regimes, precise numerical…

Superconductivity · Physics 2011-01-06 Mark C. Sweeney , Martin P. Gelfand

In planar structures, the vortex resonance frequency changes little as a function of an in-plane magnetic field as long as the vortex state persists. Altering the topography of the element leads to a vastly different dynamic response that…

Phase transitions between different (i.e. giant and multi-vortex) superconducting states and between the superconducting-normal state of mesoscopic disks and rings are studied in the presence of an external magnetic field by solving the two…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 F. M. Peeters , V. A. Schweigert , B. J. Baelus , P. S. Deo

We investigate theoretically the spin torque and magnetization dynamic in a thin ferromagnetic (FM) layer with spatially varying magnetization. The FM layer is deposited on the surface of a topological insulator (TI). In the limit of the…

Mesoscale and Nanoscale Physics · Physics 2013-03-29 Ji Chen , Mansoor Bin Abdul Jalil , Seng Ghee Tan

We study the interface physics of bipartite magnetic materials deposited on a topological insulator. This comprises antiferromagnets as well as ferrimagnets and ferromagnets with multiple magnetic moments per unit cell. If an energy gap is…

Mesoscale and Nanoscale Physics · Physics 2017-04-24 Stefan Rex , Flavio Nogueira , Asle Sudbø

We examine a stochastic Landau-Lifshitz-Gilbert equation for a frustrated ferromagnet with competing first and second order exchange interactions exposed to deterministic and random spin transfer torques in form of transport noise. We prove…

Probability · Mathematics 2023-06-29 Beniamin Goldys , Chunxi Jiao , Christof Melcher

Electric field control of magnetic structures, particularly topological defects in magnetoelectric materials, draws a great attention in recent years, which has led to experimental success in creation and manipulation by electric field of…

Strongly Correlated Electrons · Physics 2017-05-24 P. I. Karpov , S. I. Mukhin

We consider the Landau-Lifshitz equation for the spin torque oscillator - a uniaxial ferromagnet in an external magnetic field with polarised spin current driven through it. In the absence of the Gilbert damping, the equation turns out to…

Pattern Formation and Solitons · Physics 2020-04-22 I. V. Barashenkov , Alexander Chernyavsky

We derive a continuum equation for the magnetization of a conducting ferromagnet in the presence of a spin-polarized current. Current effects enter in the form of a topological term in the Landau-Lifshitz equation . In the stationary…

Materials Science · Physics 2009-10-30 Ya. B. Bazaliy , B. A. Jones , Shou-Cheng Zhang

A molecular Mott insulator $\kappa$-(ET)$_2$B(CN)$_4$ [ET = bis(ethylenedithio)tetrathiafulvalene] with a distorted triangular lattice exhibits a quantum disordered state with gapped spin excitation in the ground state. $^{13}$C nuclear…

Ferromagnetism is typically discussed in terms of the exchange interaction and magnetic anisotropies. Yet real samples are inevitably affected by the magnetostatic dipole-dipole interaction. Because of this interaction, a theorem (R.B.…

Statistical Mechanics · Physics 2025-01-27 D. Pescia , A. Vindigni

The stress caused by vortices in tetragonal superconductors contributes to the intervortex interaction which depends on vortex orientation within the crystal, on elastic moduli, and is attractive within certain angular regions even in…

Superconductivity · Physics 2015-06-17 V. G. Kogan

The melting transition of the vortex lattice in highly anisotropic, layered superconductors with commensurate, periodic columnar pins is studied in a geometry where magnetic field and columnar pins are normal to the layers. Thermodynamic…

Superconductivity · Physics 2009-11-07 Chandan Dasgupta , Oriol T. Valls

The magnetic field $h_z$ of a moving Pearl vortex in a superconducting thin-film in $(x,y)$ plane is studied with the help of time-dependent London equation. It is found that for a vortex at the origin moving in $+x$ direction, $h_z(x,y)$…

Superconductivity · Physics 2021-02-02 V. G. Kogan , N. Nakagawa

We discuss the unconventional magnetic response and vortex states arising in noncentrosymmetric superconductors with chiral octahedral and tetrahedral ($O$ or $T$) symmetry. We microscopically derive Ginzburg-Landau free energy. It is shown…

Superconductivity · Physics 2020-12-04 Albert Samoilenka , Egor Babaev

We investigate the behavior of vortices of multi-component superconductivity, realized in $\rm{MgB_2}$ and Fe-based superconductors, within the framework of Ginzburg-Landau (GL) theory in terms of numerical calculations of the…

Superconductivity · Physics 2011-12-05 Shi-Zeng Lin , Xiao Hu

A spin wave is the disturbance of intrinsic spin order in magnetic materials. In this paper, a spin wave in the Landau-Lifshitz-Gilbert equation is obtained based on the assumption that the spin wave maintains its shape while it propagates…

Mesoscale and Nanoscale Physics · Physics 2019-10-25 Zhiwei Sun , Jingrun Chen
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