Field distribution of magnetostatic waves in a tangentially magnetized ferromagnetic slab

The field distribution of magnetostatic surface and volume waves as they propagate at an arbitrary angle to a constant field in a tangentially magnetized ferromagnetic slab (Damon-Eschbach waves) is investigated. Snapshots of the magnetic field lines of the wave are constructed. The variation of the magnetic field distribution with thickness is qualitatively identified for a volume wave as it propagates at an angle equal to the cutoff angle of the surface wave, as a result of which the sinusoidal profile of the wave over thickness almost discontinuously acquires an additional phase difference. Zh. Tekh. Fiz. 69, 82–86 (January 1999)     

Indicatrices of magnetostatic surface waves

Indicatrices (isofrequency curves) of magnetostatic surface waves are studied with allowance for wave attenuation. A bias magnetic field is applied tangentially to a ferrite film. Arbitrary angles between the bias magnetic field and the wave vector are examined.     

Propagation of magnetostatic waves in the form of rectangular pulses in YIG films

The effect of dispersion on the propagation of linear rectangular pulses of magnetostatic waves in YIG films is studied. With surface magnetostatic waves propagating in YIG films and composite ferrite-insulator-metal structures, it is demonstrated that, for the near-rectangular phase-unmodulated input pulse and the distance between input and output transducers equal roughly to half the dispersion length of the pulse, the FWHM of the output pulses is 50–60% of the initial value. This fact can be used for estimating the dispersion coefficient of magnetostatic waves.     

Parametric excitation of spin waves in a nonlinear magnetostatic resonator

A theory of spin wave parametric instability is developed that simultaneously allows for cubic anisotropy and first- and second-order uniaxial anisotropies. The contributions of various anisotropies to a dispersion relation and first-and second-order nonlinearity coefficients are considered. A technique for studying the parametric instability of oscillations in magnetostatic resonators that relies on measuring their Q factors is proposed. Measuring data are used to determine the relaxation frequencies of parametrically excited spin waves in yttrium iron garnet films at frequencies close to 1 GHz. It is shown that a nonlinearity in the bias dependence of the spin wave frequencies should be allowed for in studying the relaxation parameters of ferrites.     

Nonlinear surface magnetostatic waves in a ferrite semiconductor structure

A theoretical analysis is made of the propagation of a nonlinear surface magnetostatic wave in a planar ferrite semiconductor structure as a function of the carrier concentration in the semiconductor layer. It is shown that for certain concentrations the surface magnetostatic wave is unstable with respect to longitudinal perturbations and may propagate perpendicular to the magnetic field in the form of solitons. Zh. Tekh. Fiz. 69, 119–121 (June 1999)     

Cross-phase modulation of surface magnetostatic spin waves

This paper explains the modulation instability of two surface magnetostatic spin waves simultaneously propagating in a ferromagnetic film. Self-modulation of the spin waves appears when their power reaches a threshold, and this is a sign of cross-phase modulation. The parameters of the unstable process are calculated, and the gains of the perturbation amplitudes are determined. The results published earlier on the experimental detection of the cross-phase modulation of spin waves are explained. Zh. éksp. Teor. Fiz. 116, 2058–2068 (December 1999)     

Wave front reversal of surface magnetostatic waves

The wave front reversal (WFR) of non-reciprocal waves has been investigated. The experiment was performed using surface magnetostatic waves (SMSW) excited by a pulsed microwave signal of the carrier frequency ∼4.7 GHz in an epitaxial yttrium–iron garnet (YIG) film. The WFR was realized by pulsed parametric pumping of a double frequency. It was shown that WFR with high efficiency can be achieved for SMSW having relatively small wavenumbers k∼10² rad/cm.     

Attenuation of surface magnetostatic waves in coupled ferrite plates

Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, Vol. 32, No. 11, pp. 1422–1429, November, 1989.     

Dispersion characteristics of surface magnetostatic waves with dissipation

It is shown that unlike undamped waves, the dispersion characteristics of spin surface waves with dissipation have a maximum wave number at which there is a downward reversal in the dispersion curve of a wave number. This forms the upper branch of a dispersion curve with inverse dispersion and high attenuation, leading to an unclear frequency dependence of the wave vector. The lower primary dispersion branch corresponds to waves with forward dispersion, and attenuation is proportional to the small parameter of dissipation. However, the coefficient of wave attenuation grows sharply near the maximum wave number. Some angular and frequency limits of surface wave propagation change as well.     

Features of surface and volume magnetostatic waves in a tangentially magnetized slab

A special direction of the wave vector was found for volume magnetostatic waves (MSWs) that coincides with the cutoff angle for surface MSWs; when crossing this direction, the field configuration for MSWs with small wavenumbers changes sharply. It is shown that this direction corresponds to the maximum asymmetry of magnetostatic potential distribution over the film depth and the largest wave penetration depth into the film bulk from the surface. This effect occurs also for volume MSWs propagating in a wave channel.     

Self-localized nonlinear surface magnetic polaritons in a ferromagnetic medium

The properties of electromagnetic waves propagating in a semibounded, nonlinear, ferromagnetic medium are investigated. It is shown that under certain conditions the interaction between the spin and electromagnetic waves results in the localization of volume polaritons near the surface. Self-localization of surface polaritons due to the nonlinear properties of the medium occurs thereby. The nonlinear Schrödinger equation for nonlinear surface and volume polaritons is derived, and the conditions under which solitons of these waves exist are determined. The wave intensity required to observe the predicted effects is estimated.     

Transformation of surface magnetostatic waves channeled by a step bias field

The propagation of magnetostatic waves in a waveguide ferromagnetic channel formed by exposing a ferromagnetic film to a step bias is simulated. Both weak and strong channel couplings are considered. The dispersion characteristics and the distributions of wave functions are calculated. It is shown that the amplitudes of “half-waves” fitting into the channel width alternately increase and decrease with increasing frequency and the half-waves pass into the channel with the largest bias.     

Propagation of nonlinear pulses of magnetostatic waves in coupled magnonic crystals

A periodic structure in the form of two coupled magnonic crystals in which the coupling allows effective control of nonlinear effects during propagation of magnetostatic waves is examined. The main specific features of the nonlinear effects are revealed in comparison with the periodic structure in the form of one magnonic crystal. The ability of the nonlinear coupler to suppress high- or lower-power signals for the functional processing of microwave-frequency signals is demonstrated.     

Wideband chaotic oscillation in a self-oscillatory system with a nonlinear transmission line on magnetostatic waves

Wideband chaotic microwave oscillation in a ring self-oscillatory system is studied. The system includes a solid-state power amplifier and a wideband nonlinear transmission line with a ferromagnetic film in which magnetostatic waves of different types are excited. It is found that the eigenmodes of the self-oscillatory system excited in the passband of the transmission line on magnetostatic waves become noisy because of spin wave parametric excitation due to the magnetostatic wave and nonlinearity of the power amplifier. A continuous spectrum of modes observed in the wideband chaotic signal is associated with the presence of a descending portion in the dynamic characteristic of the nonlinear transmission line, which arises when a magnetostatic surface wave is excited.     

Effect of magnetocrystalline anisotropy on the temperature characteristics of magnetostatic waves in ferromagnetic films

The temperature dependence of the eigenfrequencies of magnetization oscillation in a single-crystal film is shown to depend strongly on the temperature dependence of the magnetocrystalline anisotropy field. The conditions are considered under which the temperature coefficient of the ferromagnetic resonance frequency in a film with cubic anisotropy changes sign as the orientation of the magnetization vector is changed from the 〈111〉 to the 〈100〉 direction. The spectrum of surface magnetostatic waves is investigated experimentally in 〈110〉-oriented yttrium iron garnet films. It is established that, due to magnetic anisotropy of the ferrite, the temperature dependence of the long-wavelength limit of the frequency spectrum becomes nonmonotonic when a film of this material is magnetized along the 〈100〉 axis.     

Magnetically tunable Airy-like beam of magnetostatic surface spin waves

In this Letter,we report an Airy-like beam of magnetostatic surface spin wave(Ai BMSSW)supported on the ferromagnetic film,which is transferred from the optical field.The propagation properties of Ai BMSSW were verified with micromagnetic simulation.From simulation results,the typical parabolic trajectory of the Airy-type beam was observed with an exciting source encoding 3/2 phase pattern.The simulation results coincide well with design parameters.Furthermore,simulated results showed that the trajectories of the Ai BMSSW could be tuned readily with varied external magnetic fields.This work can extend the application scenario of spin waves.     

Bragg diffraction of surface magnetostatic waves from magnetic lattices

We present a theoretical and experimental investigation of Bragg scattering of surface magnetostatic waves (SMSW) by a time-independent, spatially periodic magnetic field when the wave orientation is arbitrary with respect to the magnetization field. In the theoretical section the theory of single-mode Bragg diffraction is generalized to the case of waves with arbitrary dispersion propagating through an anisotropic medium. The calculated results are, on the whole, supported by experimental measurements on SMSW. We demonstrate that a geometry which in isotropic media leads to a sinusoidal distribution of diffraction order amplitudes as a function of penetration into the differing lattice, can lead to a nearly exponential distribution of such amplitudes in anisotropic media. The anisotropy of the interaction between SMSW and the magnetic diffracting lattice is manifested by anomalously high scattering efficiencies for certain cases of relative orientation.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 76–85, November, 1988.     

Propagation of surface magnetostatic waves in a one-dimensional magnon crystal of a variable thickness

The propagation of surface magnetostatic waves in a ferromagnetic film of variable thickness having a planar periodic structure in the form of a grating of etched parallel strips (one-dimensional magnon crystal) has been investigated. The dispersion characteristics of surface magnetostatic waves have been calculated using the Wentzel-Kramers-Brillouin method. The intrinsic error of the method has been estimated, and the magnon spectrum of the surface magnetostatic wave has been studied. An analysis of the dispersion characteristics and the transmission capacity of these structures has demonstrated that they can be used for designing narrow-band and comb filters.     

Bragg interaction of surface magnetostatic waves with a periodic granular HTSC structure

The Bragg interaction of surface magnetostatic waves with periodic granular HTSC structure has been investigated. The dispersion equation for the coupled waves has been obtained. Resonant absorption of waves near the critical temperature involving the granular structure of the superconductor has been found. The possibility of using the observed effect for making frequency-selective structures and high-speed bolometric photodetectors is shown. Tomsk University. Radio Electronic and Control Systems. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 94–98, October, 1997.