ISSN 0869-6632 (Print)
ISSN 2542-1905 (Online)

Innovations in applied physics

Influence of three-magnon decays on electromotive force generation by magnetostatic surface waves in integral YIG – Pt structures

The purpose of this work is to find out the influence of three-magnon decay processes on the electromotive force (EMF (U)) generated by propagating magnetostatic surface waves (MSSW) with the help of the inverse spin Hall effect in the “yttrium-iron garnet (YIG) – platinum (Pt)” structure. Methods. The experiments were carried out using the delay line structures based on YIG films with the thickness of 8.8 and 14.6 µm, on the surface of which antennas were formed for MSSWs excitation and reception and a Pt film between antennas. Results.

Tunable spin-wave delay line based on ferrite and vanadium dioxide

One of the key elements for modern microwave circuits is a delay line, which is widely utilized for the signal generation as well as processing. Spin-wave delay lines based on ferrite films provide a high delay time and small dimensions. Typically, the performance characteristics of such lines are tuned by the variation of an externally applied magnetic field characterized by some drawbacks. The phenomenon of a metal–insulator transition (MIT) in the phase change materials permits to improve the performance characteristics of the spin-wave delay lines.

Spin-wave diagnostics of epitaxial ferrite-dielectric structures

Purpose of this study is to elucidate the mechanism of transformation of electromagnetic and exchange spin waves (ESW) in a thin transition layer of epitaxial ferrite–dielectric structures, as well as to investigate the possibilities of using short-wave ESW to diagnose magnetic inhomogeneities of epitaxial yttrium-iron garnet (YIG) films. Methods. In this paper, we study the hybridization processes of electromagnetic and exchange spin waves that occur in the transition layer of the YIG film.

Magnetic metasurfaces with metallic inclusions

Purpose of this paper is the development and creation of the magnetic metasurfaces with metallic inclusions operating both in the microwave and terahertz frequency ranges. Methods. The Maxwell’s equations and the expressions for the effective medium parameters are used to build the analytical models of the magnetic metasurfaces based on either a ferromagnetic (FM) or antiferromagnetic (AFM) dielectric matrix, containing a two-dimensional periodic structure of thin metal (non-magnetic) wires surrounded by insulators.

Magnetoimpedance modulation in a planar magnetoelectric ferromagnet – piezoelectric heterostructure

The effect of a giant change in the impedance of ferromagnetic materials under the action of an external magnetic field is widely used to elaborate highly sensitive magnetic field sensors. The purpose of this work was to demonstrate the possibilities of controlling the magnitude of the magnetoimpedance in a ferromagnet-piezoelectric structure using an electric field. Method.

Nonlinear amplification of the magnetic induction signal in a magnetomodulation sensor with an amorphous ferromagnetic core

The purpose of this work is to show the possibility of using a magnetic field-controlled nonlinearity of the amplitude change in an oscillatory LC-circuit containing a core made of an amorphous ferromagnetic alloy with compensated longitudinal magnetostriction, which makes it possible to obtain a high conversion coefficient of weak magnetic field sensors operating at room temperature. Methods.

About theory of extended interaction klystron and drift space in the form of medium with complex permittivity

Purpose of this work is to construct a theory of extended interaction klystron with ordinary distributed resonators, but with a drift space in the form of medium with complex permittivity. Methods. For this, a hybrid of extended interaction klystron and an amplifier with a complex permittivity is considered in the framework of the weak signal approximation. Two types of configurations of a extended interaction klystron were considered: with two and three distributed resonators.

Nonlinear Fano resonance in a coupled system magnonic microwave-guide – resonator

The purpose of research is to study of characteristics of the Fano resonance in a coupled system of nonlinear microwave-guides and resonators depending on geometric parameters of the systems, magnitude of the coupling between them, and the intensity of spin waves. Methods. Linear and nonlinear spin-wave excitations in lateral systems of irregular microwaveguides and resonators based on films of yttrium iron garnet are considered.

Mathematical modeling of a low-voltage multibeam klystron of millimeter range

The purpose of this work is to determine the efficiency of low-voltage multibeam klystrons in the Ka-frequency range, using an electron-optical klystron-analog system operating in the Кu-range. Methods. The natural frequencies and main dimensions of the resonators were found by solving the Maxwell equations by the finite difference method in the time domain (FDTD) with a rectangular spatio-temporal partition grid.

Multilayer field emitters on a thin metal substrate

The purpose of this work is to determine the ability of creating multilayer cathodes from contacted materials with different work functions ef on thin metal substrates, as well as the practical use of such cathodes for the formation of intense sheet and annular in cross sections electron flows in miniature but high-voltage devices. Methods.