Tunable band gaps in a layered structure magnonic crystal-ferroelectric

A dispersion relation for a hybrid electromagnetic-spin wave in a layered structure magnonic crystal-ferroelectric has been derived. The main distinctions of the band gaps in this structure from those in a single magnonic crystal have been determined. It is shown that the characteristics of these zones can be tuning by the electric field.     

Studying the spectra of thermal magnons in composite materials with embedded magnetite nanoparticles using Brillouin light-scattering spectroscopy

We describe the preparation of multilayer composite coating comprising nanoparticles of magnetite on metal substrates previously modified by sonication. Using the Brillouin light-scattering method, we have investigated the spectral characteristics of thermal magnons in these films as a function of the number of layers and the external magnetic-field strength.     

Effect of magnetized ferromagnetic film on electrodynamic characteristics of a meander microstrip line

The results of an experimental investigation of electrodynamic characteristics of a meander microstrip line with a ferromagnetic film are presented for different values of an external magnetic field. It is found that, in the presence of a ferrite film, higher-order modes caused by perturbation of corresponding modes of a multilayered meander line are excited in the passband of a higher-order mode of the meander line. These modes propagate in dielectric substrates of the meander line and the ferromagnetic film. The effect of transmission of the active power in the stopband of the meander line with a ferromagnetic film is discovered. This effect also arises in the case of excitation of magnetostatic waves.     

Nonlinear suppression of microwave signals in a resonant magnetostatic wave transmission line

We have studied the phenomenon of suppression of a microwave signal in a magnetostatic wave (MSW) resonant transmission line comprising a microstrip resonator with a tangentially magnetized ferromagnetic film. Distinctions are revealed between the observed effects and those reported for a matched MSW line transmitting one microwave signal or two signals with different power levels.     

Generation of chaotic microwave pulses with the help of passive synchronization of spin wave self-modulation frequencies in self-oscillatory ring systems

Passive synchronization (PS) of spin wave self-modulation frequencies of a chaotic microwave signal has been observed for the first time in a self-oscillatory ring system involving a nonlinear passive element with saturable absorption. The development of PS led to the generation of a periodic train of chaotic microwave pulses with an off/duty ratio exceeding 20. It is established that the repetition period of chaotic microwave pulses can be controlled by changing gain in the ring system.     

Generation of chaotic microwave pulses in broadband self-oscillating ring system with ferromagnetic film under the action of external pulse-modulated microwave signal

We have experimentally studied specific features of the generation of chaotic microwave pulse trains in a self-oscillating ring system with nonlinear delay line on surface magnetostatic waves, bandpass filter, and power amplifier on GaAs field-effect transistors under the action of an external pulse-modulated microwave signal occurring outside the band of the generated chaotic signal. It is established that a decrease in the off/duty ratio in the external pulse-modulated microwave signal leads to an increase in this ratio for the chaotic microwave pulses. The integral power of the chaotic microwave signal generated under the pulsed external signal action is increased as compared to the power of signal generated in the autonomous regime.     

Generation of chaotic microwave pulses in a ring system based on a klystron power amplifier and a nonlinear delay line on magnetostatic waves

The autonomous generation of stationary chaotic microwave pulse trains in a self-oscillating ring system with a multicavity klystron power amplifier operating in a small-signal regime and a wideband non-linear delay line on surface magnetostatic waves has been experimentally studied. It is established that the characteristics of generated chaotic microwave pulses can be controlled by varying the electron beam current and accelerating voltage in the klystron.     

Generation of parametric bright solitons in ring self-oscillating systems with multiresonant ferromagnetic and vacuum elements

Parametric bright solitons in ring self-oscillating patterns with ferromagnetic films are studied experimentally and theoretically. It is demonstrated that such structures can be formed due to the three-wave parametric instability of the magnetostatic surface wave and the time dispersion produced in the ring by different multiresonant elements: a klystron amplifier or a magnonic quasi-crystal with Fibonacci structure.     

Propagation of compound signals via a nonlinear magnetostatic-wave transmission line

The results of an investigation into the specific features of the propagation of a two-frequency signal and modulated signals via a microstrip-resonator-ferromagnetic-film system in the case of excitation of magnetostatic backward volume waves are presented. A nonlinear model in the form of an equivalent circuit, whose parameters functionally depend on both the input-signal power level and the frequency detuning between the large signal and the small signal, is proposed. The results of the calculations performed using the proposed model are compared to the experimental data.     

A nonlinear model of a microstrip transmission line with a ferromagnetic film in the presence of excited magnetostatic waves

A method is proposed for constructing a nonlinear mathematical model of a microstrip line with a ferromagnetic film in the presence of excited magnetostatic surface waves. The method uses multiobjective optimization and regression analysis of the data obtained from a multifactorial designed experiment. The adequacy and accuracy of calculations performed with the model constructed are confirmed by comparison with experimental results. Dependences of the radiation impedance of a line with particular parameters on the power of the input signal are calculated for different values of the external magnetic field and frequency.