This study investigates the structure and properties of discrete breathers (DBs) in a linear chain of magnetic nanoparticles, considering the effects of dissipation. Using numerical modeling based on the Landau-Lifshitz-Gilbert equation, we analyze the dynamics of magnetization in a chain of ellipsoidal nanoparticles interacting via dipole-dipole coupling. Dissipation significantly impacts both the lifetime and frequency evolution of DBs. Our results show that DBs exhibit localized magnetization oscillations that decay over time, eventually leading to spin wave emission. We explore how variations in particle spacing affect DB formation and properties, revealing that shorter distances between particles strengthen dipole-dipole interactions, thus reducing DB lifetime. It is shown that dissipation not only suppresses DBs, but transforms them into a source of spin wave-packet with a controlled speed. These findings provide insights into the nonlinear dynamics of magnetic nanoparticles and offer potential applications in magnonics and spintronics.

The article is aimed at computer modeling of giant magnetic resistance in thin antiferromagnetic films in an external magnetic field. Computer simulation uses the Monte Carlo method and Ising antiferromagnetic model to describe the magnetic properties of the film. Metropolis’ algorithm forms the spin states of the film. The semi-classical model describes the movement of electrons through the crystal lattice of the film. The electron participates in chaotic thermal motion and drift under the influence of an electric field. The external magnetic field creates magnetization in the antiferromagnetic film. The magnetic moment of the film affects the movement of electrons through the exchange interaction between the spins of atoms and electrons. The simulated system includes a non-magnetic conductive film and an antiferromagnetic film. The spinpolarized electric current is injected through a non-magnetic film. Simulations showed two mechanisms for electrical resistance growth. The first mechanism is associated with electron filtration at the interface between the non-magnetic film and the antiferromagnetic film. The second mechanism is associated with the formation of domains acting as impurities and leading to electron scattering. These two mechanisms give maximum resistance at different magnetic field strengths. The addition of these two mechanisms gives a nonlinear law of magnetoresistance growth as the magnetic field increases.

The study investigates the magnetization dynamics in one-dimensional chains of elliptical magnetic nano-particles interacting via dipole-dipole interactions. Numerical simulations of the Landau-Lifshitz (LL) equations demonstrate the possibility of localized nonlinear high-amplitude magnetization oscillations in such nano-particle chains, which manifest as discrete breathers (or intrinsic localized modes). These solutions consist of a "core," where the magnetization vectors precess around a hard axis, and "tails," where they oscillate around the equilibrium state. Analytical estimations of the breather frequency agree well with the numerical simulation results. The influence of the nanoparticles' geometrical parameters on discrete breathers in a linear chain is determined. Analysis of the frequency expression shows that breathers can exist only when one of the principal axes-specifically, the one oriented perpendicular to the chain direction-is significantly smaller than the other two; that is, when the particles are nearly disk-shaped.

The results of study of the behavior of surface plasmon polaritons in the layered structure of a VO2‒SiO2-graphene-based hyperbolic metasurface under the influence of an external magnetic field before and at the beginning of the phase transition of vanadium dioxide are presented. As a result of calculations, it is shown how the isofrequency contour of surface plasmons changes taking into account the different direction of the external magnetic field. It is also shown how an external magnetic field affects the direction of static magnetization caused by the inverse Faraday effect. This work can offer additional ways to control the behavior of surface plasmons, as well as become the basis for the study of new self-adjusting structures.

The article aims to study the effect of polarized electric current on the magnetization in antiferromagnetic film by computer modeling. Research uses the Ising model, Monte Carlo method, and Metropolis algorithm. The model considers a two-layer film made of a non-magnetic conductor and a conductive antiferromagnetic film. Spin-polarized electric current is supplied through the lower boundary of the nonmagnetic film. The system simulates a sandwich system of ferromagnetic and antiferromagnetic films separated by a non-magnetic spacer. The role of ferromagnetic film is reduced to the polarization of electric current. Simulations have been carried out for different temperatures. The computer simulation examines the dependence of the magnetization in the antiferromagnetic film on the current strength and the polarization of the electron stream. A computer experiment showed the presence of a current threshold for an antiferromagnetic film well below the Neel temperature. The threshold value depends on the temperature and polarization of the electron stream. In the antiferromagnetic phase, there is a maximum magnetization that can be achieved with spin transfer torque. The current threshold and magnetization limit disappear when approaching the Neel temperature.

The effect of temperature, external magnetic field, and non-magnetic substrate on a two-dimensional magnet with a skyrmion structure was studied by Monte Carlo simulation. The skyrmion structure was ensured by the presence of the Dzyaloshinskii–Moriya interaction and anisotropy in the energy of the system. The effect of the substrate was described by the Frenkel–Kontorova potential.

In this work we theoretically analyze the electromagnetic behavior of graphene-based metasurface, consisting on arranged array of graphene stripes, under attenuated total reflection conditions. We investigate surface plasmon-polaritons excitation at terahertz and sub-terahertz frequencies. We show that surface plasmon-polaritons may be excited in the metasurface for some orientation with respect to incident wave plane. Effectivity of surface plasmon-polaritons excitation depends on graphene chemical potential and graphene stripes width. We believe that our results open a new road for graphene metasurface based terahertz devices, such as modulators.

This paper considers the modeling of surface plasmon polaritons excitation in a limited nanostructure on the basis of a two-dimensional area discrete model, the area interacts with the oscillator. The nanostructure is a rectangle defined on the metal surface at the interface of the gold–silicon oxide, the surface plasmon–polaritons are excited by an electromagnetic radiation point source located above the metal surface. The dynamics of radiation point source is described by a discrete version of the Van der Pol equation with a small nonlinearity of the source parameters. The parameters of the goldsilicon oxide structure (the wave phase speed, the radiation source frequency, the characteristic time in the system, etc.) will be received from the dispersion relation for surface plasmon–polaritons at a single metal–dielectric interface. The distributions of the wave field in the structure will be analyzed at different positions of the point oscillator and different coupling coefficients of the wave field with the oscillators. The resonant wave field mode composition at different positions of the point oscillator and different coupling coefficients will be found using the two-dimensional Fourier transform of the wave field, the time evolution of excited modes of the wave field amplitudes will be also analyzed. In conclusion, the paper gives applicability limits of the considered model for studying the surface plasmon polaritons excitation in a limited nanostructure.

In this Letter we demonstrate a fundamentally new, to the best of our knowledge, concept to enhance the magnetic modulation of the surface plasmon polaritons (SPPs) by using hybrid magneto-plasmonic structures consisting of hyperbolic plasmonic metasurfaces and magnetic dielectric substrates. Our results show that the magnetic modulation of SPPs in the proposed structures can be an order of magnitude stronger than in the hybrid metal-ferromagnet multilayer structures conventionally used in active magneto-plasmonics. We believe that this effect will allow for the further miniaturization of magneto-plasmonic devices.

The paper proposes a mathematical model for describing the movement of the working body of the plow, taking into account the vibration effect. The model is used to simulate the movement of the working body of the plow with an uneven speed of the traction unit. It was found that when accelerating, a stationary displacement of the working body of the plow occurs, as well as a decrease in the amplitude of oscillations and an exit to a stationary mode with a small amplitude of several millimeters. The specific power also reaches a stationary value over time. The parameters of steady oscillations depend on the stationary value of the speed of movement and the properties of the soil.

This article performs computer simulations of the change in magnetization in the ferromagnetic film when polarized electric current passes through it. The model examines multilayer structures from ferromagnetic and nonmagnetic films. A sandwich system comprises two ferromagnetic layers separated by a nonmagnetic gasket. Ferromagnetic films have different magnetic susceptibility. The first ferromagnetic film is magnetically hard and acts as a fixed layer. The second ferromagnetic film is magnetically soft, with a switched direction of magnetization. The current direction is perpendicular to the film plane (CPP geometry). Spin transfer is carried out by electrons that polarize in the first ferromagnetic film and transmit spin to the second ferromagnetic film. We use the Ising model to describe the magnetic properties of the system and the Metropolis algorithm to form the thermodynamic states of the spin system. Simulations are performed at temperatures below the Curie points for both materials. The result of computer simulation is the dependence of magnetization in the magnetically soft film on the current strength in the system. Calculations show that there is a critical value of the current at which the magnetization sign of the controlled film changes. The magnetization versus current plot is stepwise. The change in the magnetization sign is due to an increase in the polarization of the electron gas. The plot of electron gas polarization versus current is also stepwise.

The paper considers a nanowires 2D array located in the nodes of a square lattice. Computer simulations use the Heisenberg model and Metropolis algorithm. The array consists of small nanowires that are monodomain. The exchange interaction orders the spins within a single nanowire. Dipole–dipole forces act between neighboring nanowires. The shape of an individual nanowire affects its magnetic anisotropy. Computer simulations examine the phase transition temperature and magnetization behavior of the system. The type of magnetic moments ordering in the array of nanowires depends on the orientation of their long axis. We consider two types of systems. The nanowires’ long axes are oriented perpendicular to the plane of their location in the first case. A dipole–dipole interaction results in first-type superantiferromagnetic ordering of the nanowires’ magnetic moments for such orientation. The nanowires’ long axes are oriented in the plane of the system in the second case. Dipole–dipole interaction results in second-type superantiferromagnetic ordering in such systems. The dependence of the phase transition temperature on the dipole–dipole interaction intensity is investigated.

We analyze resonant magnetoelastic interactions between standing perpendicular spin wave modes (exchange magnons) and longitudinal acoustic phonon modes in free-standing hybrid metal-ferromagnet bilayer and trilayer structures. Whereas the ferromagnetic layer acts as a magnetic cavity, all metal layers control the frequencies and eigenmodes of acoustic vibrations. The design proposed here allows for achieving and tuning the spectral and spatial mode overlap between phonons and magnons that results in their strong resonant interaction. Realistic simulations for gold-nickel multilayers show that sweeping the external magnetic field should allow for observing resonantly enhanced interactions between individual magnon and phonon modes in a broad range of frequencies spanning from tens of gigahertz up to several hundreds of gigahertz, which can be finely tuned through the multilayer design. Our results would enable the systematic study and the deep understanding of resonantly enhanced magnetoelastic coupling between individual phonon and magnon modes up to frequencies of great contemporary fundamental and applied interest.

We present a theoretical study of the substrate influence on the electrical and magnetic properties of a one-dimensional multiferroic. We used a one-dimensional axial next-nearest neighbor Ising model (1D ANNNI model). The effect of the substrate was modeled using the periodic Frenkel–Kontorova potential. It is shown that the periodic potential of the substrate reduces the polarization of the multiferroic at low temperatures. The substrate potential significantly affects the structural changes near the magnetic phase transition temperature.

We have investigated the substrate influence on the Curie temperature of 2D magnet using the simple Ising model on a square lattice and the Frenkel–Kontorova potential for the substrate. We have found that the change in the phase transition temperature is directly proportional to the gradient of the exchange integral and the period of the substrate. The incommensurate arrangement of atoms with respect to the substrate potential leads to complex effects, such as the influence of the substrate potential and the coverage coefficient on the phase transition in the spin system. Moreover, the phase transition temperature can be increased or decreased, either the coverage coefficient is θ<1 or θ>1. Our results will help to understand deeply the effect of substrate on magnetic properties of 2D magnets.

We investigate the magnetic phase transition in a thin film with an antidote lattice by computer simulation. A lattice of non-magnetic antidotes is present in a thin film of several atomic layers. The antidotes form a rectangular lattice. We are looking at two forms of antidotes. The Ising model and Wolf' cluster algorithm simulate the system's magnetic behavior. Antidotes act on additional surfaces of the system. This results in a change in the Curie temperature of the system. Dependence of phase transition temperature on holes size and shape is obtained. The phase transition temperature depends on the size of the hole by logarithmic law. The Curie temperature for triangular holes is lower than for square holes. We investigated the magnetization of a thin film with an antidote lattice and constructed a hysteresis loop. The hysteresis loop expands as the hole size decreases. Coercive force depends on the size and shape of the holes. Coercive force varies by nonlinear law.

Magneto-optical (MO) effects, viz. magnetically induced changes in light intensity or polarization upon reflection from or transmission through a magnetic sample, were discovered over a century and a half ago. Initially they played a crucially relevant role in unveiling the fundamentals of electromagnetism and quantum mechanics. A more broad-based relevance and wide-spread use of MO methods, however, remained quite limited until the 1960s due to a lack of suitable, reliable and easy-to-operate light sources. The advent of Laser technology and the availability of other novel light sources led to an enormous expansion of MO measurement techniques and applications that continues to this day (see section 1). The here-assembled roadmap article is intended to provide a meaningful survey over many of the most relevant recent developments, advances, and emerging research directions in a rather condensed form, so that readers can easily access a significant overview about this very dynamic research field. While light source technology and other experimental developments were crucial in the establishment of today’s magneto-optics, progress also relies on an ever-increasing theoretical understanding of MO effects from a quantum mechanical perspective (see section 2), as well as using electromagnetic theory and modelling approaches (see section 3) to enable quantitatively reliable predictions for ever more complex materials, metamaterials, and device geometries. The latest advances in established MO methodologies and especially the utilization of the MO Kerr effect (MOKE) are presented in sections 4 (MOKE spectroscopy), 5 (higher order MOKE effects), 6 (MOKE microscopy), 8 (high sensitivity MOKE), 9 (generalized MO ellipsometry), and 20 (Cotton–Mouton effect in two-dimensional materials). In addition, MO effects are now being investigated and utilized in spectral ranges, to which they originally seemed completely foreign, as those of synchrotron radiation x-rays (see section 14 on three-dimensional magnetic characterization and section 16 on light beams carrying orbital angular momentum) and, very recently, the terahertz (THz) regime (see section 18 on THz MOKE and section 19 on THz ellipsometry for electron paramagnetic resonance detection). Magneto-optics also demonstrates its strength in a unique way when combined with femtosecond laser pulses (see section 10 on ultrafast MOKE and section 15 on magneto-optics using x-ray free electron lasers), facilitating the very active field of time-resolved MO spectroscopy that enables investigations of phenomena like spin relaxation of non-equilibrium photoexcited carriers, transient modifications of ferromagnetic order, and photo-induced dynamic phase transitions, to name a few. Recent progress in nanoscience and nanotechnology, which is intimately linked to the achieved impressive ability to reliably fabricate materials and functional structures at the nanoscale, now enables the exploitation of strongly enhanced MO effects induced by light–matter interaction at the nanoscale (see section 12 on magnetoplasmonics and section 13 on MO metasurfaces). MO effects are also at the very heart of powerful magnetic characterization techniques like Brillouin light scattering and time-resolved pump-probe measurements for the study of spin waves (see section 7), their interactions with acoustic waves (see section 11), and ultra-sensitive magnetic field sensing applications based on nitrogen-vacancy centres in diamond (see section 17). Despite our best attempt to represent the field of magneto-optics accurately and do justice to all its novel developments and its diversity, the research area is so extensive and active that there remains great latitude in deciding what to include in an article of this sort, which in turn means that some areas might not be adequately represented here. However, we feel that the 20 sections that form this 2022 magneto-optics roadmap article, each written by experts in the field and addressing a specific subject on only two pages, provide an accurate snapshot of where this research field stands today. Correspondingly, it should act as a valuable reference point and guideline for emerging research directions in modern magneto-optics, as well as illustrate the directions this research field might take in the foreseeable future.

This article investigated the magnetic properties of a 2D nanolattice through computer modeling. A square antidote nanolattice in thin films was considered. For our computer simulation, we used the Heisenberg model. Ferromagnetic phase transition was studied for lattices with pores of various sizes. We determined the Curie temperature based on the finite-dimensional scaling theory. Using Wolf's algorithm, we simulated the behavior of the system. The dependence of the phase transition temperature on the density of spins was found to be power. Using Metropolis' algorithm, we calculated a hysteresis loop for an antidote lattice film. The hysteresis loop narrowed as the pore sizes increased. The dependence of coercive force on the size of the nanolattice obeyed the logarithmic law.

The formation of the substrate surface potential based on the Lennard-Jones two-particle potential is investigated in this paper. A simple atom’s square lattice on the substrate surface is considered. The periodic potential of the substrate atoms is decomposed into a Fourier series. The amplitude ratio for different frequencies has been examined numerically. The substrate potential is approximated with high accuracy by the Frenkel–Kontorova potential at most parameter values. There is a field of parameters in which the term plays a significant role, with a period half as long as the period of the substrate atoms. The ground state of the monoatomic film is modeled on the substrate potential. The film may be in both crystalline and amorphous phases. The transition to the amorphous phase is associated with a change in the landscape of the substrate potential. There are introduced order parameters for structural phase transition in the thin film. When changing the parameters of the substrate, the order parameter experiences a jump when changing the phase of the film.