Magnetostatic Wave Propagation Research Articles

MSSW and MSVW in a multilayered ferrimagnetic structure with an arbitrary orientation between two static magnetizations

A study of both magnetostatic surface wave (MSSW) and magnetostatic volume wave (MSVW) propagation in multilayered magnetic thin films with noncollinear magnetizations is presented. A YIG/GGG/YIG structure is used (YIG and GGG refer to yttrium iron garnet and gadolinium gallium garnet, respectively). The layered film is in the

Microwave pulse frequency modulator based on magnetostatic waves

A new type of microwave frequency modulator based on magnetostatic wave (MSW) propagation in a nonstationary magnetised garnet film providing any smooth modulation law is proposed and investigated. The formation of linear frequency modulated (LFM) pulses with 1.2 GHz carrier frequency, 4 μs duration and 10 MHz frequency deviation has been demonstrated.

MSVW propagation in multilayered magnetic structures with non-collinear magnetizations

The authors present a study of magnetostatic volume wave (MSVW) propagation in multilayered magnetic thin films with non-collinear magnetizations. YIG/GGG/YIG structure is used. The layered film is in the

Influence of vortex motion on magnetostatic wave propagation in the ferrite-high temperature superconductor layered structure.

The influence of the mixed state of type II superconductor on magnetostatic wave (MSW) dispersion and absorption is theoretically investigated. The MSW characteristics are shown to depend on the relationship between the MSW a.c. field penetration depth into superconductor 1, wavelength λ and superconductor thickness b. The former is expressed in terms of an effective conductivity, which is strongly dependent on the d.c. vortex velocity vo due to a d.c. current. If vo exceeds the MSW phase velocity, instead of absorption of the wave, we have its amplification. The effect of d.c. voltage generation owing to the dragging of vortices by MSW is also studied.

An efficient numerical spectral domain method to analyze a large class of nonreciprocal planar transmission lines

Presents an efficient numerical application of the Galerkin method in the spectral domain (SD) to the analysis of striplike/slotlike coplanar transmission lines embedded in a bianisotropic multilayered medium. The method is based on obtaining the spectral dyadic Green's function by the equivalent boundary method (EBM), a suitable third order extraction technique of the asymptotic behavior of the Green's dyad, an enhanced numerical integration scheme, and the use of an adequate contour integral method for searching zeros in the complex plane. This method, namely the SD-EBM, has been found to be very suitable for analyzing transmission lines with semiconductors and/or ferrites magnetized at an arbitrary direction, including the study of magnetostatic wave propagation phenomena. >

Magnetostatic-wave propagation in media with finite electrical conductivity

The wave propagation of magnetostatic surface waves (MSSWs) is formulated in terms of the vector instead of the scalar potential theory. The present formulation of the MSSW propagation accounts for the impact of the finite conductivity of ground planes and dielectric layers and the associated losses in the film stacks. The method can handle the two-dimensional wave propagation in any plane parallel film stack. The complex dispersion equation is explicitly derived for a stack with two ground planes being located at finite distances at opposite sides from the central magnetic film. Numerical results for this configuration are presented. It is shown that the dispersion curves break up into a number of branches and that contrary to the lossless case no maxima and minima with zero group velocity occur. It is shown that the surface-wave like excitations occur within a much wider frequency band than predicted by the standard scalar theory.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Influence of GGG substrate on FMR and magnetostatic wave propagation

We analyse and review effects concerning the influence of the paramagnetic GGG substrate on FMR at low temperatures and magnetostatic wave propagation in ferrimagnetic garnet films. New experimental data are presented for the permeability of GGG at X band.

Nonlinear effects accompanying magnetostatic wave propagation in the ferrite-high temperature superconductor structure

The influence of superconductor nonlinearity on magnetostatic wave propagation in the ferrite-superconductor layered structure is studied. The linear and nonlinear phenomena relative to wave amplitude are discussed. They are: the wave instability due to superconductor negative differential conductivity and the constant voltage generation due to vortex dragging by the wave.

Multistable magnetostatic waves in thin film

A theory of the propagation of nonlinear magnetostatic surface waves in a ferromagnetic film with a periodically corrugated surface is presented. It is shown that the filter characteristics of this nonlinear periodic structure exhibits bistable or multistable properties above a threshold power so that, for a given input power of the wave, several values of output power are possible.

Magnetostatic wave propagation in YIG double layers

Calculations are presented for the magnetostatic surface wave propagation characteristics in single-crystal yttrium-iron-garnet (YIG) double layers with arbitrary direction of magnetization. The induced uniaxial magnetic anisotropy field is assumed to be different in the two layers; hence, the magnetization in one layer is aligned at an angle with respect to the magnetization direction in the other layer. The magnetostatic field interactions between layers depend on the angle between the two magnetization directions and on the separation between the two YIG layers. The wave propagation directions and time delays in each layer can be strongly affected by the use of an applied magnetic field and the magnetostatic coupling between the two layers, as well as by the uniaxial anisotropy energy in each layer.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Structure and conductivity of CoMnNiO multi-composition amorphous thin film

In this paper, the results of the theoretical studies of magnetostatic surface wave (MSSW) propagation in layer-photosensitive semiconductor-ferrite waveguides when the external electromagnetic wave affects the semiconductor surface are reported. Dispersion relation of MSSW has been found and the effects of various intensities of electromagnetic wave on the propagation characteristics have been examined. It has been shown that MSSW propagation loss can decrease and there is a frequency band in which MSSW has amplification with increasing intensity of the external light.

Crystalline anisotropy and loss effects on magnetostatic waves in layered yttrium iron garnet films

We report the effects of cubic and uniaxial anisotropy on the propagation of magnetostatic waves. When yttrium iron garnet films grown by the method of liquid-phase epitaxy on a [111] plane are biased in plane, the magnetization is aligned with the bias field only at six special orientations. In addition to frequency band shifts, the cubic anisotropy results in magnetostatic surface wave modes which have tilted plane phase fronts. Furthermore, the dB/μs loss of magnetostatic surface waves in multiple-layer films is not constant but varies with frequency.

Anisotropy and loss effects on MSWs in layered ferrite films (abstract)

The effects of cubic anisotropy on the resonance and magnetostatic wave (MSW) propagation properties of thin and lossy YIG films are discussed. It is known that cubic anisotropy fields result in a misalignment between the magnetization vector and the applied magnetic field.1,2 We show that when the applied field is in a plane perpendicular to the [111] crystallographic axis of the YIG cubic lattice the misalignment can be avoided in some special cases. We give expressions for the permeability tensor in these special cases and we show that the cubic anisotropy renders surface waves with piecewise planar-phase fronts. The phase of the surface mode is different at the two sides of the YIG film. This phase shift can be used to characterize the cubic anisotropy of YIG films. In addition, loss effects are discussed and the insertion loss of composite modes in layered structures is compared with the traditional dB/μs loss figures of single-film modes.

Continuous steering of MSSW waves in YIG double layers

In this paper we report on the calculations for the magnetostatic wave propagation characteristics in single-crystal double layers of yttrium iron garnet with arbitrary direction of magnetization. The induced uniaxial magnetic anisotropy field is assumed to be different in the two layers, and hence the magnetization in one layer is aligned at an angle with respect to the magnetization direction in the other layer. The magnetostatic surface wave propagations with the greatest bandwidths and the maximum energy deliveries in each layer can be strongly affected by the application of an applied magnetic field and the magnetostatic coupling between the two layers.

Passage of surface magnetostatic waves through magnetic 'valley' and 'ridge'

The propagation of magnetostatic surface waves (MSSWs) in a ferrite film magnetized by a nonuniform magnetic bias field in the shape of a magnetic valley or a magnetic ridge has been investigated theoretically and experimentally. The MSSW beam paths and the beam profiles have been studied at different frequencies for different angles of orientation of the input MSSW transducer relative to the direction of the bias magnetic field. It is noted that the results obtained can aid in the construction of microwave MSSW devices with nonuniform bias fields.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Observation of dipole spin wave envelope solitons in ferromagnetic films

The formation of spin-wave (SW) envelope solitons was observed in experiments on dipolar SW (or magnetostatic wave) propagation in yttrium-iron-garnet (YIG) films magnetized at a small angle ( theta /sub e/ >

Propagation of acoustic surface waves in periodic structures

This review covers the propagation of acoustic surface waves (ASW) in periodic structures. The authors discuss the main types of ASW: Rayleigh waves, Gulyaev?Bleustein waves, Love waves. Shear surface waves which can propagate along a periodically uneven surface of an elastic solid are described in detail. The authors rigorously treat the Bragg reflection of ASW from periodic arrays of grooves on the substrate for the cases of normal, oblique, and side incidence. Reciprocal conversion effects between bulk and surface waves in an array whose period is close to the ASW wavelength are discussed, together with such related effects as the interaction between Rayleigh waves and Lamb modes, acoustic wave transmission through a gap in a piezoelectric material, etc. Laser excitation of ASW and magnetostatic wave propagation in periodic structures are also reviewed.

Finite-element analysis of magnetostatic wave propagation in a YIG film of finite dimensions

A unified numerical approach based on the finite-element method is described for the magnetostatic wave propagation in a YIG film of finite dimensions. Both magnetostatic surface wave modes are treated. The validity of the method is confirmed by calculating the magnetostatic wave modes in a YIG-loaded rectangular waveguide and in a YIG film of finite width. The numerical results of a YIG films with nonuniform bias field along the film width are also presented, and the effects of bias field distributions on the delay characteristics and potential profiles are examined.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Epitaxial growth of highly Bi-substituted garnet films with narrow FMR linewidth and low optical absorption loss

The epitaxial growth of highly Bi-substituted iron garnet films on gadolinium gallium garnet (GGG) substrates prepared by the LPE (liquid-phase-epitaxy) technique is investigated. The growth temperatures are carefully controlled so as to obtain crack-free films. A ferromagnetic resonance (FMR) linewidth of 0.6 Oe was measured, which is the smallest value reported to date for such films. The optical characteristics of the films are discussed. Magnetostatic surface wave propagation was observed in the prepared films. As the prepared films have low FMR linewidth, low optical absorption and high Faraday rotation, they have good potential for magnetostatic-wave-based optical waveguide devices.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Three- and four-magnon decay of nonlinear surface magnetostatic waves in thin ferromagnetic films.

The propagation of nonlinear monochromatic surface magnetostatic waves in thin ferromagnetic films is investigated. It is shown that these waves are unstable above a certain threshold intensity causing satellite waves to be excited through magnon decay processes. It is shown that the small value of the threshold intensity is consistent with first-order (three-magnon) effects. In the regime where these effects are forbidden, another higher threshold intensity exists that is due to second-order (four-magnon) effects. Analytical forms for the threshold intensities, together with numerical estimates, are also presented.