Yurii P. Sharaevskii

Self-Generation of Chaotic Dissipative Soliton Trains in Active Ring Resonator With 1-D Magnonic Crystal

Self-generation of chaotic dissipative soliton trains was observed in an active ring resonator based on 1-D periodical ferromagnetic structure (1-D magnonic crystal) in a grooves grating form. The grooves were cut off on the surface of yttrium iron garnet film with the help of a scribing technique and placed perpendicularly to the magnetostatic surface wave (MSSW) propagation. The presence of three magnon decay processes of MSSW, a frequency filtration, and a passive synchronization of the spin-wave self-modulation frequencies caused the self-generation of chaotic dissipative soliton trains. Passive synchronization was realized at frequencies of the first band gap because of the presence of a saturable absorption of a microwave signal.

Magnonic Bandgap Control in Coupled Magnonic Crystals

The periodic structure in the form of two coupled magnonic crystals (MCs) was considered for the first time. It was shown that the variation of coupling allows to control effectively the characteristics of the bandgaps in the spectrum of magnetostatic spin waves. Main features of formation of the bandgaps were investigated in the basis of theoretical and experimental results. The comparison with a periodic structure in the form of a single MC was provided. The possibility of formation of two frequency bandgaps and shift of the frequency bandgaps depending on coupling was demonstrated in the frequency region of the first Bragg resonance. It was shown that the control of bandgaps in such structure gives additional opportunities to create microwave filters and phase shifters with desired characteristics.

Generation of Chaotic Microwave Pulses in Ferromagnetic Film Ring Oscillators Under External Influence

This study reports on the experimental results of chaotic microwave (MW) pulse generation in a ferromagnetic film ring oscillator under pulse-modulated (PM) and narrowband noise forces. Chaotic dynamics of the investigated self-oscillatory system is produced through three-wave parametric interactions of spin waves. It is shown, that periodical sequences of chaotic MW pulses are generated under a PM force and solitary chaotic MW pulses are generated under a noise force. Such pulses are formed through forced chaos synchronization. For description of forced chaos synchronization phenomenon, a ferromagnetic film ring oscillator model with nonlinear amplification and delay time is constructed. This model is based on the use of the Landau-Lifshitz equation, magnetostatic approximation and the Holstein-Primakoff transformation. Calculation results of chaos suppression under an external harmonic force are demonstrated.

Tunable Bandgaps in Layered Structure Magnonic Crystal–Ferroelectric

The spectral characteristics of the hybrid spin-electromagnetic waves in multiferroic layered structure magnonic crystal (MC)-ferroelectric were theoretically and experimentally investigated. The main features of the bandgaps formation in such a structure were compared with the case of a single MC. The possibility of the bandgap characteristics control with varying electric field is demonstrated.

Dissipative Soliton Oscillator With a Nonlinear Spin Wave Transmission Line and a Signal-to-Noise Enhancer in the Feedback Loop

This study reports on a dissipative soliton oscillator utilizing two nonlinear magnetostatic spin wave (MSW) devices in a feedback loop. Both nonlinear MSW devices [a spin wave transmission line (TL) and a signal-to-noise enhancer (SNE)] operate in the frequency band where three-wave parametric processes are allowed. Self-generation of a complex-modulated MW signal is caused by nonlinearity of the spin wave TL. The SNE carries out a passive locking of the spin wave self-modulation frequencies and forms the dissipative soliton trains. It is shown, that electronic control of a repetition interval and pulse ratio of dissipative solitons is realized by the change of a klystron beam current.

Nonlinear Magnetostatic Wave Propagation through One Dimensional Finite Magnonic Crystals

A model describing the propagation of surface magnetostatic waves in the one-dimensional finite length magnonic crystal (MC) with losses was constructed. The features of microwave pulse passing through the band gap of MC were investigated experimentally. The conditions of soliton-like pulse formation were defined experimentally and by numerical simulation.

Spatial and Temporal Dynamics of Dissipative Parametric Solitons in a Ferromagnetic Film Active Ring Resonator

This paper reports the experimental results of spatial and temporal dynamics research of dissipative parametric solitons generated in a ferromagnetic film active ring resonator. Such dissipative structures are formed through three-wave parametric decay of a magnetostatic surface wave and frequency-time filtering. The spatio-temporal dynamics of dissipative parametric solitons has been investigated using the Brillouin light scattering technique. It is shown that quasi-stationary temporal structures are formed in a ring along a ferromagnetic film and are not observed in a ferromagnetic film, which is not incorporated into the ring.

Spin-Wave Switching in the Side-Coupled Magnonic Stripes

This study of the spin waves coupling in the magnonic coupler, formed by the laterally coupled magnonic stripes, is performed by the means of finite-element and micromagnetic simulations. The efficiency of the spin-wave coupling is improved by the geometry design and choice of the appropriate magnetization direction inside each magnonic stripe. The proposed side-coupled magnetic stripes enable the improvement of performance of the advanced integrated magnonic devices and offer a range of further opportunities in planar magnonics.

Self-Generation of Parametric Soliton-Like Pulses in a Magnonic Quasi-Crystal Active Ring Resonator

This paper reports theoretical results of a parametric soliton-like pulse self-generation in an active ring resonator by using magnonic quasi-crystal (MQC) with Fibonacci-type structure. For the calculation of MQC transmission responses, the model based on the transfer matrix method is used. Besides, the model of the MQC active ring resonator that contains three perimetrically coupled differential equations and two differential equations of linear oscillators is used to calculate the parametric soliton-like pulse self-generation. It is established that such pulses are self-generated all over the range of the external static magnetic field values where three-wave parametric decay of the magnetostatic surface wave is allowed. The minimal threshold of the soliton-like pulse self-generation is observed at high values of a magnetic field. This threshold is increased at any value of a magnetic field when a magnonic crystal is used in a feedback loop.

Nonlinear switching of spin waves in the side-coupled magnonic stripes

The development of magnonic micro and nanosized elements leads to the fabrication of functional devices for planar magnonic applications [1–3].