Alexey B. Ustinov

Multifunctional nonlinear magnonic devices for microwave signal processing

A multifunctional microwave spin-wave device utilizing a ferrite-film magnonic crystal is reported. A principal of operation of the device is based on a nonlinear frequency shift and a nonlinear damping of the carrier spin waves propagating in the magnonic crystal. The device performs several functions of microwave signal processing, namely, enhancement of signal-to-noise ratio, limiting or suppression of high-power signals, and power-dependent phase shift.

A spin-wave logic gate based on a width-modulated dynamic magnonic crystal

An electric current controlled spin-wave logic gate based on a width-modulated dynamic magnonic crystal is realized. The device utilizes a spin-wave waveguide fabricated from a single-crystal Yttrium Iron Garnet film and two conducting wires attached to the film surface. Application of electric currents to the wires provides a means for dynamic control of the effective geometry of waveguide and results in a suppression of the magnonic band gap. The performance of the magnonic crystal as an AND logic gate is demonstrated.

A microwave nonlinear phase shifter

A microwave nonlinear phase shifter is described. It is a device producing a power-dependent phase shift of microwave signals. The device is fabricated with a ferrite film which serves as a waveguide for magnetostatic spin waves. A nonlinear phase shift of the carrier spin waves appearing under increasing their power is the key phenomenon in the device operation. A theoretical model for the nonlinear phase shifter is presented. The model provides a good description for the experimentally obtained performance characteristics of the device.

Power-dependent switching of microwave signals in a ferrite-film nonlinear directional coupler

The authors report the realization of a microwave nonlinear directional coupler based on a ferrite film. It is a passive device for direct signal processing at microwave frequencies. The power-dependent switching of microwave signals is demonstrated. The switching is achieved through a differential nonlinear phase shift of the operating spin waves propagating in the ferrite film.

Ferrite-film nonlinear spin wave interferometer and its application for power-selective suppression of pulsed microwave signals

A theoretical model of the nonlinear spin wave interferometer has been developed. An experimental prototype of the device has been manufactured and investigated. The device application for power-selective suppression of pulsed microwave signals has been demonstrated. The obtained experimental data are in good agreement with the theory.

Nonlinear multiferroic phase shifters for microwave frequencies

A nonlinear microwave phase shifter based on a planar multiferroic composite has been studied. The multiferroic structure is fabricated in the form of a bilayer consisting of yttrium iron garnet and barium strontium titanate. The principle of operation of the device is based on the linear and nonlinear control of the phase shift of the hybrid spin-electromagnetic waves propagating in the bilayer. The linear control is realized with magnetic and electric fields. The nonlinear control is provided by the input power of microwave signal. The device showed a nonlinear phase shift up to 250°, electric field induced phase shift up to 330°, and magnetic field induced phase shift of more than 180°.

All-thin-film multilayered multiferroic structures with a slot-line for spin-electromagnetic wave devices

Spin-electromagnetic waves propagating in thin-film multilayered multiferroic structures containing a slot transmission line have been investigated both experimentally and theoretically. The thin-film structure was composed of a ferrite film, a ferroelectric film, and a slot-line. It was shown that the spectrum of the spin-electromagnetic wave was formed as a result of hybridization of the spin wave in the ferrite film with the electromagnetic wave in the slot-line and was electrically and magnetically tunable. For the experimental investigations, a microwave phase shifter based on the multiferroic structure has been fabricated. Performance characteristics are presented.

Dispersion characteristics of spin-electromagnetic waves in planar multiferroic structures

A method of approximate boundary conditions is used to derive dispersion relations for spin-electromagnetic waves (SEWs) propagating in thin ferrite films and in multiferroic layered structures. A high accuracy of this method is proven. It was shown that the spin-electromagnetic wave propagating in the structure composed of a thin ferrite film, a thin ferroelectric film, and a slot transmission line is formed as a result of hybridization of the surface spin wave in the ferrite film and the electromagnetic wave in the slot-line. The structure demonstrates dual electric and magnetic field tunability of the SEW spectrum. The electric field tunability is provided by the thin ferroelectric film. Its efficiency increases with an increase in the thicknesses of the ferrite and ferroelectric films and with a decrease in the slot-line gap width. The theory is confirmed by experimental data.

Nonlinear phase shifters based on forward volume spin waves

A microwave nonlinear phase shifter based on forward volume spin waves (FVSWs) is studied. The device is fabricated with perpendicularly magnetized 5.2-μm thick single-crystal yttrium iron garnet film. The performance characteristics of the device are measured for the bias magnetic field of 1850–3700 Oe. The obtained results show that the nonlinear phase shifter produces a power-dependent phase shift of a microwave signal. The nonlinear phase shift (NLPS) appears with the signal power increasing and demonstrates almost linear rise up to 180°. With constant incident microwave power, the NLPS is a decreasing function of the bias magnetic field. A nonlinear damping of the FVSWs restricts the linear rise of the device output power with incident power increasing. The experimental data are in good agreement with theory. The phenomenological parameters describing the FVSWs nonlinear damping are determined.

Magnetically Tunable Microwave Spin-Wave Photonic Oscillator

A magnetically tunable microwave spin-wave photonic oscillator was designed and modeled. A spin-wave filter made with an yttrium-iron garnet (YIG) film was used simultaneously as a frequency-selective and time-delay element. Frequency tuning of the oscillator was realized in the range of 4-8 GHz through the variation of a bias magnetic field applied to the YIG film. The phase noise was -125 dBc/Hz at 10 kHz offset and -140 dBc/Hz at 100 kHz offset from the oscillation frequency.