Spatial Distribution of the Amplitudes of Electromagnetic Waves Propagating in a Bounded Multilayer Structure with Periodic Irregularity

The step-by-step method is used for the analysis of propagation of electromagnetic waves in a multilayer structure of a finite length with periodic irregularities of the permittivity, permeability, and conductivity. The distribution of the wave amplitudes in the structure layers is considered and two its main types, sinusoidal and exponential, are revealed. Passbands and stopbands in frequency dependences of reflection and transmission coefficients are found. Parameters of these passbands and stopbands are determined by the combination of the periodicity of irregularities and the finiteness of the structure length. In the case of the tensor permeability, an additional stopband caused by gyrotropic properties of the magnetic medium is found. For the case of a conducting medium, the excess of the normalized amplitude of propagating waves over the unit level is considered and possible factors that cause its appearance are discussed.     

Application of the averaging method to calculation of propagation of electromagnetic radiation through thin films with different conductivities

The averaging method is used for calculation of the reflection and transmission coefficients of a 1D longitudinal electromagnetic wave and a 1D transverse electromagnetic wave that are incident along the normal onto a plane-parallel plate. The averaged electrodynamic boundary conditions are derived for an arbitrary conductivity of the plate. It is demonstrated that the averaging method enables one to simplify the calculations and resulting expressions owing to a decrease in the order of the system of equations and elimination of trigonometric functions. The error of this method is several percent for planes with thicknesses up to 0.35 of the wavelength in the medium.     

Multiplicative Frequency Conversion in a Scheme of Magnetostrictive Transducer. Frequency Multiplication in the Continuous Regime

Journal of Communications Technology and Electronics - Oscillations of magnetization and elastic displacement in a ferrite plate that is normally magnetized with respect to the plate plane are...     

Multiple frequency transformation in the magnetostriction transducer: Frequency division in the relaxation mode

The forced oscillations of the magnetization and elastic displacement in the normally magnetized ferrite plate with magnetoelastic properties are discussed. The process whereby the initial frequency is divided in the ratio defined by the multiplicity of the resonance frequencies of magnetic and elastic subsystems is investigated. The time and amplitude characteristics of the phenomenon are revealed on the basis of the impact excitation model of an elastic system under short-term magnetic actions. Recommendations are given for the practical implementation of excitation-frequency division in the scheme of a magnetostriction transducer.     

Reflection and refraction of acoustic waves at the insulator-ferromagnetic heusler alloy boundary

Reflection and refraction of longitudinal and transverse acoustic waves on a flat boundary between an insulator and a ferromagnetic crystal of a Heusler alloy Ni_{2 + x + y} Mn_{1 − x} Ga_{1 − y} have been considered in the region of premartensitic and martensitic phase transitions. The possibility is shown of using temperature to effectively controlling the angles of wave refraction and the coefficients of transformation of wave modes by changing strong acoustic crystalline anisotropy induced with approaching the point of the phase transition. The conditions of the appearance of critical angles and the angles of total internal reflection, as well as the effect of temperature on them, have been considered. The possibility has been analyzed of emission, in the vicinity of the phase transition, of a wave that propagates along the boundary into the bulk of the material. Based on the experimental data obtained by Trivisonno for the temperature dependences of the sound velocity in the Ni_{2 + x + y} Mn_{1 − x} Ga_{1 − y} crystal, the conclusions of the theory developed are illustrated by numerical calculations for a concrete structure, namely, Ni₂MnGa-quartz.     

An algorithm for determination of the amplitudes of reflected and transmitted waves in the case when counterpropagating waves are incident on a multilayer stepwise inhomogeneous structure

A simple algorithm is proposed for derivimg analytical expressions for the amplitudes of reflected and transmitted waves in the case when two 1D counterpropagating waves are incident on a multilayer stepwise inhomogeneous structure. Wave amplitudes are analytically expressed for structures consisting of three, four, and five layers. The proposed algorithm is applied to solve numerically the problem of wave propagation in an inhomogeneous structure where the wave number linearly changes along the structure’s length. The algorithm involves approximation of a smooth inhomogeneity by a step one. A criterion and conditions are obtained for the applicability of the step approximation for the investigation of wave propagation through inhomogeneous media with smoothly varying parameters. It is shown that the algorithm can be applied to problems on propagation of electromagnetic waves in the cases of the normal and oblique incidence.     

The second-order magnetization precession in an anisotropic medium. Part 2: The cubic anisotropy

The second-order precession of the magnetization vector in a normally magnetized magnetic plate with the cubic anisotropy is considered for the [001], [011], and [111] orientations of the axes of a cubic cell along the static field. The precession pattern of the forced oscillation in the form of a large ring and small rings located along the envelope is obtained. A relationship between the observed high- and low-density groups of small rings and the spatial position of the [111] easy magnetization axes is revealed and explained on the basis of the energy model of the potential. It is found that the phenomenon is highly sensitive to the orientation of cubic axes, the anisotropy constant, and the intensities and directions of the static and alternating fields. It is reported that the observed phenomena can be used in practice.     

An algorithm for determination of the amplitudes of external and internal waves in the case of counterpropagating waves incident on a multilayer structure with a step inhomogeneity

A simple algorithm is proposed for deriving analytic expressions for the amplitudes of reflected, transmitted, and internal waves in individual layers of a multilayer stepwise inhomogeneous structure with an arbitrary number of layers. Functioning of the algorithm is exemplified by the solution of problems of wave propagation in a stepwise inhomogeneous structure with the wave number variation along the structure’s length.     

Multiplicative Frequency Conversion in a Scheme of Magnetostrictive Transducer. Frequency Multiplication in the Relaxation Regime

Journal of Communications Technology and Electronics - Stimulated oscillations of magnetization and elastic displacement in a normally magnetized ferrite plate with magnetoelastic properties are...