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We demonstrate the dissipative spatiotemporal patterns that are generated by an active ring resonator based on a magnonic quasicrystal (MQC) with Fibonacci-type structure. The dissipative patterns are formed through the magnetostatic surface spin-wave (MSSW) parametric decay into exchange spin waves (SWs), temporal dispersion of the ring resonator and amplification. In the spatial domain, the MSSW and SW parametric patterns measured with the help of Brillouin light spectroscopy have the quasiperiodic spatial localization in crests and grooves of the MQC, respectively. In contrast to the optical quasiperiodic parametric spatial conservative solitons, the amplitude profiles of the magnonic quasiperiodic parametric spatial dissipative patterns correspond to the profiles of the crests and grooves of the MQC. In the time domain, the packets of the chaotic parametric pulses, which are analogs of temporal solitons, are generated at each point of the spatial patterns. The chaotic nature of such pulses is confirmed by an estimate of a highest Lyapunov exponent from the experimental time series. The pulse packets are formed through the time-filtering technique using the external microwave (MW) pulses to control a ring gain. It is shown that at a certain duty factor of the external MW pulses, the parametric MSSW pulses have the amplitude and phase profiles corresponding to the profiles of a conservative bright envelope soliton.

We present the results of experimental studies of the oscillation regimes of the pulse signals, which are analogs of the temporal solitons, in a distributed active ring resonator with a multicavity klystron amplifier and a spin-wave transmission line. The soliton-like pulses are formed under conditions of three-wave parametric decay of a surface magnetostatic spin wave when the klystron amplifier operates in a small-signal regime. Parametric turbulence is shown to cause the chaotic nature of generated patterns, which is confirmed by the performed estimations of the senior Lyapunov exponent from experimental time series. In addition, the possibility of controlling the phase coherence, the autocorrelation time, and the noise-to-signal ratio of the generated chaotic soliton-like pulses by varying the beam current and the acceleration voltage of the klystron amplifier is demonstrated.

The main features of the nonlinear spin wave propagating in the magnonic crystal/semiconductor (SC) layered heterostructure are studied. We demonstrate the possibility of double electric and magnetic control of the gap solitons parameters (their number, threshold of formation, velocity), bistability of spin waves, switching powers and nonlinear band gap shift in investigated structure. Our results show the possibility of nonlinear magnonics and SC electronics integration based on the proposed structure.

The features of wave processes in a heterostructure based on two ferromagnetic films separated by a layer of non-magnetic dielectric layer have been investigated at different levels of the input signal power. It has been experimentally demonstrated using Brillouin light scattering set-up that at low input power it is transferred from one film to another along the length of the structure, which is typical for any spatially distributed coupled systems. At a certain level of input power the inhibition of periodic power transfer from one film to another is observed, therefore, the coupling between the films disappears. In order to explain this effect, we have developed the theory based on the model of two nonlinear equations for the amplitudes enveloping the signals in each film. Numerical calculation results are in a good agreement with experimental data.

The main features of the spin wave band structure formation and manipulation in the magnonic crystal – semiconductor layered heterostructure have been studied. We demonstrate possibility of double electric and magnetic control of band gap characteristics within the spectra of propagating spin waves. It is shown that in the magnonic crystal- semiconductor heterostructure, when a positive polarity voltage is applied to the semiconductor layer, the band gap in the spin-wave spectrum shifts to the low-frequency region, while for the negative polarity the band position is practically not changed. We show also that as the magnitude of the applied magnetic field is increased the shift of the band gap is decreased. Our results show the possibility of integration of magnonics and semiconductor electronics on the base of proposed structure.

The authors studied intracellular liver protective mechanisms in development of chronic fluorine intoxication. Findings are that synthesis of protective proteins HIF-1α, HOx-1, HOx-2 and HSP72, restricting free radical oxidation in hepatocytes increased in liver at early stages (1-3 weeks) of exposure to fluorine. At late terms of chronic fluorine intoxication (6-12 weeks), damaging effects of fluorine result from its genotixicity - ability to suppress synthesis of intracellular protective proteins and enzymes of main metabolic cycles in liver.

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.

The generation of quasi-periodic sequences of parametric soliton-like pulses in an active ring resonator with a ferromagnetic film via the three-wave parametric instability of a magnetostatic surface wave is studied theoretically and experimentally. These dissipative structures form in time due to the competition between the cubic nonlinearity caused by parametric coupling between spin waves and the time dispersion caused by the resonant cavity that is present in a self-oscillatory system. The development of dynamic chaos due to the parametric instability of a magnetostatic surface wave results in irregular behavior of a phase. However, this behavior does not break a quasi-periodic pulse sequence when the gain changes over a wide range. The generated soliton-like pulses have a chaotic nature, which is supported by the maximum Lyapunov exponent estimated from experimental time series.

Using a combination of experiment and simulation, the authors have investigated comprehensively how the spin-wave transmission across a curved magnonic waveguide is modified through rotation of an externally delivered uniform magnetic field. They reveal that, while the spin-wave transmission is reasonable when the bend is magnetized along an axis of symmetry, the transmission can be substantially improved (by a factor of 2) through just rotating the magnetic field by 15\ifmmode^\circ\else\textdegree\fi{} in a particular direction. To explain their results, the authors study the landscape of the internal magnetic field spanning the structure, and discuss how it can be tuned in order to optimally distribute the flow of anisotropic spin waves across networks of magnonic waveguides.

Recent progress in the magnon-based electronics shows that spin wave (SW) can be used as a signal carrier in the magnonic waveguiding structures operating in the GHz and THz frequency range [1–3].

A prototype of an ultrawideband (UWB) microwave chaos generator based on a nonlinear spin-wave transmission line, a multistage transistor amplifier with an output amplifier based on GaAs field-effect transistors, and a microstrip bandpass filter was constructed. The possibility of autonomous generation of a UWB chaotic microwave signal with a central frequency of 3 GHz and a total power of about 4 W in a frequency band exceeding 30% was demonstrated. The proposed chaos generator is characterized by a fairly high efficiency of about 20%.

The generation of single chaotic microwave pulses in a self-oscillating ring system with ferromagnetic film under the action of external narrow-band noise microwave signal occurring outside the band of frequencies of the chaotic microwave signal was observed. Chaotic generation emerged due to the parametric instability of the magnetostatic surface wave in the ferromagnetic film, whereas formation of single chaotic microwave pulses was caused by the absence of complete suppression of chaos under the action of narrowband noise.

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.

We demonstrate theoretically and experimentally the formation of additional bandgaps in the spectrum of spin waves in coupled magnonic crystals. We present the analytical model, which reveals the mechanism of bandgaps formation in coupled structures. In particular, the formation of one, two, or three bandgaps in the region of the first Bragg resonance is demonstrated and control of its characteristics by the variation of the complex coupling coefficient between magnonic crystals is shown. The spatially-resolved Brillouin light scattering spectroscopy and microwave measurements demonstrate the bandgap splitting in the spin-wave spectrum. The main advantage of proposed coupled structure, as compared to the conventional magnonic crystal, is the tunability of multiple bandgaps in the spin-wave spectrum, which enables potential applications in the frequency selective magnonic devices.

We report on the experimental observation of the spin wave spectrum control in a line-defect magnonic crystal (MC) waveguide. We demonstrate the possibility to control the forbidden frequency band (band gap) for spin waves tuning the line-defect width. In particular, this frequency may be greater or lower than the one of 1D MC waveguide without line-defect. By means of space-resolved Brillouin light scattering technique, we study the localization of magnetization amplitude in the line-defect area. We show that the length of this localization region depends on the line-defect width. These results agree well with theoretical calculations of spin wave spectrum using the proposed model of two coupled magnonic crystal waveguides. The proposed simple geometry of MC with line-defect can be used as a logic and multiplexing block for application in the novel field of magnonic devices.

We experimentally demonstrate spin waves coupling in two laterally adjacent magnetic stripes. By the means of Brillouin light scattering spectroscopy, we show that the coupling efficiency depends both on the magnonic waveguides' geometry and the characteristics of spin-wave modes. In particular, the lateral confinement of coupled yttrium-iron-garnet stripes enables the possibility of control over the spin-wave propagation characteristics. Numerical simulations (in time domain and frequency domain) reveal the nature of intermodal coupling between two magnonic stripes. The proposed topology of multimode magnonic coupler can be utilized as a building block for fabrication of integrated parallel functional and logic devices such as the frequency selective directional coupler or tunable splitter, enabling a number of potential applications for planar magnonics.

We demonstrate a magnonic beam splitter that works by inter-converting magnetostatic surface and backward-volume spin waves propagating in orthogonal sections of a T-shaped yttrium iron garnet structure. The inter-conversion is enabled by the overlap of the surface and volume spin wave bands. This overlap results from the demagnetising field induced along the transversely magnetised section(-s) of the structure and the quantization of the transverse wave number of the propagating spin waves (which are therefore better described as waveguide modes). In agreement with numerical micromagnetic simulations, our Brillouin light scattering imaging experiments reveal that, depending on the frequency, the incident fundamental waveguide magnonic modes may also be converted into higher order waveguide modes. The magnonic beam splitter demonstrated here is an important step towards the development of parallel logic circuitry of magnonics.