Metamaterials Laboratory

Scientific results:

1. For the first time we have developed a topology of magnonic networks, which are a system of planar bound magnetic micro- and nano-dimensional structures that play the key role when creating next-generation functional devices for information and telecommunication systems in the microwave range based on the principles of magnonics and spintronics.
2. It has been demonstrated that the use of multi-layer antiferromagnetic (AFM) structures allows to implement modes of generation, encoding, propagation and processing of information signal based on quants of spin waves — AFM magnons.
3. It has been demonstrated that developing radioelectronics components and designing information and telecommunication modules based on approaches of magnon straintronics relying on magnetic and magnetoelectric materials allows to radically reduce power consumption when conducting signal processing operations. This approach uses methods of deformation engineering and physical effects induced by mechanical deformations in solids for implementing next-generation devices of information, sensor and energy-efficient technologies and ultra-high-frequency equipment.
4. We have developed methods of transmitting information signals based on  interconnections relying on the principles of quantum and resonance opto-magnonics. It has been demonstrated that increasing the efficiency of the excitation of the quant of the spin subsystem by an electromagnetic photon allows to integrate the research domains of magnonics and photonics into the creation of prototypes of controlled interconnection modules in magnonic systems architectures based on nanostructured magnetic films.
5. The Laboratory has proposed and designed elements of the functional base for information and telecommunication systems relying on the principles of magnonics. This approach uses methods of forming three-dimensional interlayer and interelement connections in distributed systems for the implementation of prospective devices with high density of functional elements and for energy-efficient computations.
6. It has been demonstrated that on the basis of the concept of spin-wave computations it is possible to implement functional blocks of computational radioelectronics devices for the implementation of algorithms of neuromorphic computations and magnonic logic. The mentioned devices contain a layer of ferro- and antiferromagnetics for the implementation of active and passive signal processing devices on the basis of the principles of neuromorphic magnon straintronics, such as magnon logic cells  employing fuzzy logic elements, neuromorphic multiplexing and demultiplexing systems, spatial-frequency splitters and branchers for information signals in the microwave and the terahertz ranges of wavelengths.
7. On the basis of a research of the characteristics of motion of magnetic vortices in ultra-thin films we have demonstrated the possibility of creating devices for storing and transmitting information on the basis of racetrack skyrmion technologies, which are more efficient than modern hard drives.

• Analytical methods of solving differential equations and systems of equations, methods of the theory of wave equations and the method of perturbation theory is used for  computing the parameters of the propagation and the efficiency of control of the characteristics of spin-wave excitations accounting for crystallographic, magnetostaic and elastic energy in gradient magnetic microstructures.
• We are conducting research of the frequency range of excitation, phase and amplitude characteristics and their dependence on the elastic deformations of researched structures. Such an approach allows to build models, as well as theoretically describe processes in nanometer structures when changing the parameters of structures, the gradients of internal magnetic fields and to research possible methods of controlling the dynamics  of spin-wave excitations.
• As part of solving static problems of the distribution of static magnetic fields (and their gradients) in elastically-deformed magnetic microstructures of a specified topology we are using the finite-element method (FEM). This method finds wide use in solving problems of numerical modeling of the static and dynamic properties of magnetic structures and piezoelectrics.
• Solutions of dynamic problems of the excitation, propagation, interaction and control of the characteristics of spin waves in elastically-deformed gradient magnetic  microstructures is conducted by the micromagnetic modeling based on the finite-difference method in the temporal region for the Landau-Lifshitz equation with an efficient magnetic field accounting for elastic and magnetoelastic energy, and the equation of motion of an elastic medium.
• The laser scribing method is used for texturizing initially homogeneous magnetic films for the purpose of forming specified gradients of internal static magnetic fields. To create gradient microstuctures with micron and submicron topological norms, we are using  magnetic fields with characteristic film thicknesses of 0.1-10 μm.
• To create elastically deformed gradient microstructures we are using structures of the   magnetic film-piezoelectric type with various constants of magnetic and elastic interaction. To implement the mentioned structures, we are using magnetron sputtering of piezoelectric layers onto the surface of magnetic through interface layers.
• Radiophysical methods of the research of the characteristics of spin waves in the microwave range are aimed at researching the influence of magnetoelastic effects on the spectrum and amplitude-phase characteristics of coherent spin waves in gradient magnetic nanostructures.
• Optic methods of the research of the dynamics of spin-wave excitations elastically-deformed magnetic microstructures are based on the effect of Brillouin–Mandelstam light scattering (BMLS). Using BMLS we are conducting experimental research of the spatial and temporal dynamics of spin-wave excitations in researched structures in the microwave range of radio waves depending on the topology, gradients and elastic deformations.
• The method of magnetron sputtering is used for forming thin (less than 200 nm) metallic layers on piezoceramics and YIG films for supplying electric potential difference and soldering. Reactive and radio-frequency magnetron sputtering used for forming insulating layers on YIG films.

Education and career development:

• We have published the study guide «Microwave photonic crystals – a new type of periodic structures in radioelectronics» (Authors: Dmitry A. Usanov, Sergey. A. Nikitov, Alexandr V.Skripal, D. V. Ponomarev).
  
• One Doctor of Sciences and one Candidate of Sciences dissertations have been prepared and defended.
• In 2014 we conducted the first scientific conference on Brillouin spectroscopy that later became a regular international event.

Organizational and structural changes:

• We have created the research group «Magnonic crystals» as well as a unique complex for Brillouin Light Scattering (BLS) that relies on the effect of Brillouin–Mandelstam light scattering on spin waves. Using the BLS complex we will conduct experimental research of the spatial dynamics of spin waves in studied structures in the microwave and the terahertz ranges.

• An ISO 6 clean room has been equipped and a VSM-100 ADVAVAC Surface Technologies vacuum magnetron sputtering device has been installed with a set of targets made of various metals, including a platinum target, and a system for plasmonic treatment (purification) manufactured by ATTO II Diener Electronic GmbH. The equipment will be used to manufacture planar arrays of ferromagnetic structures with micron and submicron topological norms.

Other results:

• Three employees of the Laboratory have received the Award of the Government of the City of Moscow in science and technology (in radioelectronics) for young researchers.

• We have developed «Computer modeling of magnon dynamics in spintronics and terahertz electronics devices».