Dynamic Magnonic Crystal Research Articles

Classical analog of qubit logic based on a magnon Bose–Einstein condensate

Advances in quantum computing and telecommunications stimulate the search for classical systems allowing partial implementation of a similar functionality under less stringent environmental conditions. Here, we present a classical version of several quantum bit (qubit) functionalities using a two-component magnon Bose–Einstein condensate (BEC) formed at opposite wavevectors in a room-temperature yttrium-iron-garnet ferrimagnetic film. Employing micromagnetic numerical simulations, we show the use of wavelength-selective parametric pumping to controllably initialize and manipulate the two-component BEC. Next, by modeling the interaction of this BEC with a pulse- and radio-frequency-driven dynamic magnonic crystal we translate the concept of Rabi-oscillations into the wavevector domain and demonstrate how to manipulate the magnon-BEC system regarding the polar and azimuthal angles in the Bloch sphere representation. We hope that our study provides a significant stimulus on the boundary between qubit functionality and classical systems of interacting BECs, which use a subset of qubit-based algorithms.

Spin-wave switching using dynamic magnonic crystal

In this study, switching of the spin-wave propagation was investigated using an yttrium iron garnet (YIG) waveguide. A dynamic magnonic crystal (DMC) was designed to control the non-reciprocal surface spin waves. The DMC controlled the periodic modulation field on the YIG film and caused a strong Bragg reflection on the surface spin waves. The maximum effect of Bragg reflection was analyzed by the wavelet to be 95% of its intensity. The spin-wave switching by the DMC will be a promising method of carrier-flow control for constructing the integrated magnonic circuits.

Dynamic Magnonic Crystals for Measuring the Dispersion of Bulk Magnetostatic Spin Waves Caused by Magnetic Anisotropy in YIG Films

A dynamic magnonic crystal created by a surface acoustic wave that propagates in a GGG–YIG structure (gallium–gadolinium garnet–yttrium–iron garnet) is used to measure the dispersion of bulk magnetostatic waves due to the magnetic anisotropy in the YIG film. Such waves, which are called anisotropic-dipole magnetostatic waves (ADMSWs), can propagate together with surface spin waves in YIG films that are placed in a tangential magnetic field. It is shown experimentally that ADMSWs with a positive dispersion law occur in films that are grown by the liquid-phase epitaxy technique and not subjected to additional processing,. In the films that were subjected to additional processing the ADMSW dispersion law is negative when applying a piezoelectric zinc oxide film or bombarded with boron ions.

Dual-tunable ferrite-ferroelectric dynamic magnonic crystal

A dynamic magnonic crystal based on a planar multiferroic structure consisting of a ferrite and a ferroelectric layers has been designed and theoretically investigated for the first time. Spatially periodic electric field applied to the ferroelectric layer turns the regular multiferroic waveguide into periodic one. An electrodynamic model of the dynamic magnonic crystal and theoretical analysis of its performance is presented.

Dynamic magnonic crystal based on a layered ferrite–ferroelectric structure

A dynamic magnonic crystal based on a planar multiferroid ferrite–ferroelectric structure is suggested and studied. A space-periodic electric field applied to the ferroelectric layer converts a regular multi-ferroid waveguide to a periodic structure. An electrodynamic model of a dynamic magnonic crystal is constructed, and its dispersion and transfer characteristics are studied.

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.

Spectrum of normal waves in one-dimensional magnonic crystals

A general theory of the spectrum of normal waves propagating in magnetic structures with periodically modulated parameters has been developed. Based on the method of tensorial Green’s functions, spin-wave mode approach, and Floquet-Bloch theorem, a general form of the dispersion relation has been obtained for dipole-exchange spin waves propagating in a one-dimensional magnonic crystal formed by an arbitrary spatially periodic modulation of all magnetic and geometric parameters in the Maxwell’s equations and the Landau-Lifshitz equation. An original method has been proposed for taking into account an arbitrary profile of the modulation of the chosen parameters. The efficiency of the presented theory has been demonstrated using a simple example of the description of an experimental spectrum of a dynamic magnonic crystal.

Oscillatory Energy Exchange between Waves Coupled by a Dynamic Artificial Crystal

We describe a general mechanism of controllable energy exchange between waves propagating in a dynamic artificial crystal. We show that if a spatial periodicity is temporarily imposed on the transmission properties of a wave-carrying medium while a wave is inside, this wave is coupled to a secondary counterpropagating wave and energy oscillates between the two. The oscillation frequency is determined by the width of the spectral band gap created by the periodicity and the frequency difference between the coupled waves. The effect is demonstrated with spin waves in a dynamic magnonic crystal.

All-linear time reversal by a dynamic artificial crystal.

The time reversal of pulsed signals or propagating wave packets has long been recognized to have profound scientific and technological significance. Until now, all experimentally verified time-reversal mechanisms have been reliant upon nonlinear phenomena such as four-wave mixing. In this paper, we report the experimental realization of all-linear time reversal. The time-reversal mechanism we propose is based on the dynamic control of an artificial crystal structure, and is demonstrated in a spin-wave system using a dynamic magnonic crystal. The crystal is switched from an homogeneous state to one in which its properties vary with spatial period a, while a propagating wave packet is inside. As a result, a linear coupling between wave components with wave vectors k≈π/a and k′=k−2ππ/a≈−π/a is produced, which leads to spectral inversion, and thus to the formation of a time-reversed wave packet. The reversal mechanism is entirely general and so applicable to artificial crystal systems of any physical nature.