Search

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 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.

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%.

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.