arXiv subjects

E. O. Kamenetskii

Publications and source records attributed to E. O. Kamenetskii.

47 records · Page 3Linked to original sources

arXiv2007

Vortices and chirality of magnetostatic modes in quasi-2D ferrite disk particles

In this paper we show that the vortex states can be created not only in magnetically soft "small" (with the dipolar and exchange energy competition) cylindrical dots, but also in magnetically saturated "big" (when the exchange is neglected) cylindrical dots. A property associated with a vortex structure becomes evident from an analysis of confinement phenomena of magnetic oscillations in a ferrite disk with a dominating role of magnetic-dipolar (non-exchange-interaction) spectra. In this case the scalar (magnetostatic-potential) wave functions may have a phase singularity in a center of a dot. A non-zero azimuth component of the flow velocity demonstrates the vortex structure. The vortices are guaranteed by the chiral edge states of magnetic-dipolar modes in a quasi-2D ferrite disk.

cond-mat.mtrl-sci↗

arXiv2006

Bianisotropics and electromagnetics

Bianisotropics is conceived as a physical concept describing electromagnetic media which possess intrinsic mechanisms of magnetoelectric coupling. We propose the main idea of bianisotropics as a combination of two physical notions: (a) the near-field manipulation and (b) chirality. From classical laws these two notions are in an evident contradiction since manifestation of chirality in electromagnetics is usually due to effects of the field non-locality. In attempts to combine the field locality and chirality in media properties, we come to non-classical aspects, which constitute a subject of a macroscopic quantum mechanics analysis. This opens a new field of studies, which we call as the problem of bianisotropic metamaterials (BMMs).

cond-mat.mtrl-sci↗

arXiv2006

Self-Induced Quasistationary Magnetic Fields

The interaction of electromagnetic radiation with temporally dispersive magnetic solids of small dimensions may show very special resonant behaviors. The internal fields of such samples are characterized by magnetostatic-potential scalar wave functions. The oscillating modes have the energy orthogonality properties and unusual pseudo-electric (gauge) fields. Because of a phase factor, that makes the states single valued, a persistent magnetic current exists. This leads to appearance of an eigen-electric moment of a small disk sample. One of the intriguing features of the mode fields is dynamical symmetry breaking.

cond-mat.mtrl-sci↗

arXiv2005

Dynamical Symmetry Breaking in Quasistatic Magnetic Oscillations

Recent microwave experiments demonstrate the anapole-moment and magnetoelectric properties in quasi-2D ferrite particles with magnetic-dipolar-wave oscillating spectra. The theory developed in this paper shows that there are the macroscopically quantum topological effects. Quantum coherence for macroscopic systems refers to circumstances when large numbers of particles can collectively cooperate in a single quantum state. These effects are rarely observed through macroscopic measurements because statistical averaging over many states usually masks all evidence of quantum discreteness. Magnetic-dipolar oscillating modes in normally magnetized ferrite disks demonstrate properties of a Hamiltonian system. The purpose of this paper is to show that because of the adiabatic motion process for such a Hamiltonian system one has macroscopic quantum effects of symmetry breaking, magnetic currents, and eigen electric moments.

cond-mat.mes-hall↗

arXiv2004

Handedness of magnetic-dipolar modes in ferrite disks

For magnetic-dipolar modes in a ferrite, components of the magnetic flux density in a helical coordinate system are dependent on both an orientation of a gyration vector and a sign of a pitch. It gives four types of helical harmonics for magnetostatic-potential wave functions in a ferrite disk. Because of the reflection symmetry breaking, coupling between certain types of helical harmonics takes place in the reflection points. The reflection feature leads to exhibition of two types of resonances: the "right" and "left" resonances. These resonances become coupled for a ferrite disk placed in a homogeneous tangential RF magnetic field. One also observes such resonance coupling for a ferrite disk with a symmetrically oriented linear surface electrode, when this ferrite particle is placed in a homogeneous tangential RF electric field. In a cylindrical coordinate system handedness of magnetic-dipolar modes in a ferrite disk is described by spinor wave functions.

cond-mat.mes-hall↗

arXiv2004

Interaction of magnetic-dipolar modes with microwave-cavity electromagnetic fields

We discuss the problem of magnetic-dipolar oscillations combined with microwave resonators. The energy density of magnetic-dipolar or magnetostatic (MS) oscillations in ferrite resonators is not the electromagnetic-wave density of the energy and not the exchange energy density as well. This fact reveals very special behaviors of the geometrical effects. Compared to other geometries, thin-film ferrite disk resonators exhibit very unique interactions of MS oscillations with the cavity electromagnetic fields. MS modes in a flat ferrite disk are characterized by a complete discrete spectrum of energy levels. The staircase demagnetization energy in thin-film ferrite disks may appear as noticeable resonant absorption of electromagnetic radiation. Our experiments show how the environment may cause decoherence for magnetic oscillations. Another noticeable fact is experimental evidence for eigen-electric-moment oscillations in a ferrite disk resonator.

cond-mat.mes-hall↗

arXiv2004

Mesoscopic quantized properties of magnetic-dipolar-mode oscillations in disk ferromagnetic particles

Magnetic dipolar mode or magnetostatic (MS) oscillations in ferrite samples have the wavelength much smaller than the electromagnetic wavelength at the same frequency and, at the same time, much larger than the exchange interaction spin wavelength. This intermediate position between the electromagnetic and spin wave (exchange interaction) processes reveals very special behaviors of the geometrical effects. It was shown recently that magnetic dipolar mode oscillations in a normally magnetized ferromagnetic disk are characterized by discrete energy levels resulting from the structural confinement. In this article we give results of the energy spectra in MS wave ferrite disks taking into account nonhomogeneity of the internal DC magnetic field.

cond-mat.mes-hall↗

arXiv2003

On implementation of ferrite magnetostatic/magnetoelectric particles for quantum computation

We consider an implementation of quantum gates for quantum computation using magnetostatic/magnetoelectric (MS/ME) macroscopically quantized states in small ferrite disks. Confinement phenomena for MS oscillations in a normally magnetized ferrite disk show typical atomic properties like discrete energy levels. Because of discrete energy eigenstates of MS oscillations, the oscillating system is described as a collective motion of quasi-particles - the light magnons. A macroscopic quantum analysis of MS oscillations underlines the physics of quantized ME oscillating spectrums in ferrite disks with surface electrodes. We discuss possible technologies for physical realization of new logic gates based on MS/ME-particle qubits.

cond-mat.mes-hall↗

arXiv2003

The anapole moments in disk-form MS-wave ferrite particle

The anapole moments describe the parity-violating parity-odd, time-reversal-even couplings between elementary particles and the electromagnetic (EM) field. Surprisingly, the anapole-like moment properties can be found in certain artificially engineered physical systems. In microwaves, ferrite resonators with multi-resonance magnetostatic-wave (MS-wave) oscillations may have sizes two-four orders less than the free-space EM wavelength at the same frequency. MS-wave oscillations in a ferrite sample occupy a special place between the pure electromagnetic and spin-wave (exchange) processes. The energy density of MS-wave oscillations is not the electromagnetic-wave density of energy and not the exchange energy density as well. These microscopic oscillating objects -- the particles -- may interact with the external EM fields by a very specific way, forbidden for the classical description. To describe such interactions, the quantum mechanical analysis should be used. The presence of surface magnetic currents is one of the features of MS oscillations in a normally magnetized ferrite disk resonator. Because of such magnetic currents, MS oscillations in ferrite disk resonators become parity violating. The parity-violating couplings between disk-form ferrite particles and the external EM field should be analyzed based on the notion of an anapole moment.

cond-mat.mes-hall↗

arXiv2003

Energy Spectra of Magnetostatic Oscillations in Ferrite Disk Resonators

Ferromagnetic resonators with short-wavelength, so-called magnetostatic (MS), oscillations can be considered in microwaves as point (with respect to the external electromagnetic fields) particles. It was shown recently [E. O. Kamenetskii, Phys. Rev. E, 63, 066612 (2001)] that MS oscillations in a small ferrite disk resonator can be characterized by a discrete spectrum of energy levels. This fact allows analyzing the MS oscillations similarly to quantum mechanical problems. In this paper we give the results of energy spectrum calculations for MS oscillations in a ferrite disk resonator.

cond-mat.mes-hall↗

arXiv2003

Magnetic artificial atoms based on thin-film ferrite disk particles

Semiconductor quantum wells can be considered as an example of artificial atoms. Following the ideas used in the effective-mass theory, one can describe electron states in the quantum-well structure based on the Schrodinger-like equation for the envelope function. In recent years, there has been a renewed interest in high frequency dynamic properties of finite size magnetic structures. In a series of new publications, confinement phenomena of high-frequency magnetization dynamics in magnetic particles have been the subject of much experimental and theoretical attention. Till now, however, there are no phenomenological models of a ferrite particle with high-frequency magnetization dynamics that use the effective-mass approximation and the Schrodinger-like equation to analyze energy eigenstates of a whole ferrite-particle system, similarly to semiconductor quantum wells. Magnetostatic (MS) oscillations in ferrite samples have the wavelength much smaller than the electromagnetic wavelength at the same frequency and, at the same time, much larger than the exchange-interaction spin wavelength. This intermediate position between the pure electromagnetic and spin-wave (exchange-interaction) processes reveals very special behaviors of the geometrical effects. The confined effects for MS oscillations in normally magnetized thin-film ferrite disks demonstrate very unique properties of artificial atomic structures.

cond-mat.mes-hall↗