This paper presents an overview of various types of organometallic frameworks (MOFs), their structural features, and classification. The main methods and approaches to the synthesis of both MOFs and composite materials based on them are also considered.
The structure of MOFs is a regular three-dimensional lattice formed by organic linkers and metal clusters. The nature of interconnections and types of metals can significantly affect the spatial structure and size of MOF crystals. MOFs can be nano-, micro-, and meso-sized, dense and porous, bulk and layered. This all determines their wide range of properties and applications.
Particular attention is paid to the prospects and ways to control and manipulate the shape of crystals, their size, and the spatial relationships between organic components with metal ions.
This review focuses on zeolite-like frameworks (ZIFs) as the most interesting in terms of structure, synthesis, and applications in the field of materials for electrochemical current sources. Possibilities of modification and control of properties of these ZIFs and composite materials based on them by means of composition control, creation of porous structures, and introduction of impurities, including those with magnetic properties, are considered. Various variants of synthesis of complex composite materials by controlled pyrolysis of MOFs as a simple and scalable process are considered. The influence of heat treatment conditions on the final properties is demonstrated, as well as the prospects for the use of such materials in electrochemistry applications.
As one of the options for changing the properties of MOFs and composite materials based on them, an approach based on doping of MOFs with ZIF-67 structure with another metal is presented. In particular, the scientific team of the authors realized the synthesis of cobalt MOFs in which Co is partially substituted by manganese at the synthesis stage. In addition, a simple technique of synthesis by coprecipitation in aqueous solution was used, but modified by ultrasonic action, which shortens the synthesis time. Electrochemical studies showed that the specific electrochemical capacitance of electrodes made of pyrolyzed MOFs with partial substitution of cobalt for manganese is significantly higher than that of materials without manganese. Both specific capacitance and energy density increase with increasing manganese content in MOF. Mn doping of MOF allows to significantly improve (from 100 to 298 F/g at current density of 0.25 A/g) the electrochemical characteristics of electrode materials for hybrid supercapacitors based on them. The results obtained by the authors indicate that the substitution of cobalt with manganese is an effective way to improve the electrochemical characteristics of MOFs.
Thus, the article demonstrates by the example of literature review and practical experiment that the development of new approaches to the design of composite materials based on MOFs, as well as the study of physical and chemical regularities of interaction of these materials with various kinds of carriers is a very urgent task.

Charged domain walls (CDW) in ferroelectric materials are interesting from fundamental and applied points of view, since they have electrical properties different from bulk ones. At the microstructural level, CDW in ferroelectrics are two-dimensional defects that separate regions of the material with different directions of spontaneous polarization vectors. Compensation of the electric field of the bound ionic charge of the CDW by mobile carriers leads to the formation of extended narrow channels with increased conductivity in the original dielectric material. By controlling the position and angle of inclination of the CDW relative to the direction of spontaneous polarization, it is possible to change its conductivity in a wide range, which opens up broad prospects for creating memory devices, including for neuromorphic systems. The review presents the current state of research in the field of formation and application of CDW formed in single crystals of uniaxial ferroelectric lithium niobate (LiNbO₃, LN) as resistive and memristive switching devices. The main methods for forming CDW in single crystals and thin films of LN are considered, and modern data on the electrophysical properties and methods for controlling the electrical conductivity of CDW are presented. The prospects for using CDW in memory devices with resistive and memristive switching are discussed.

Silicon-carbon films are of great interest as diamond-like materials combining unique properties – high hardness, adhesion to a wide class of materials, abrasion resistance, as well as chemical resistance, low coefficient of friction and biocompatibility. The presence of silicon in the composition makes it possible to significantly reduce the internal mechanical stresses in such coatings compared to diamond ones. In modern production, films have been used primarily as solid lubricants and protective coatings. There are a large number of methods for producing silicon-carbon films, the most widespread among which are various variants of vapor-phase chemical deposition. In this paper, a method for the synthesis of silicon-carbon films was proposed and tested, based on the use of a high-frequency inductor to produce a plasma of vapors of silicon-carbon liquid injected into the chamber from an external source. Pure silicon-carbon films with a carbon atom content with sp³-hybridized orbitals of 63–65% were obtained on sitall substrates. The composition, surface roughness and coefficient of friction of unalloyed silicon-carbon films obtained by the proposed method were studied. The possibility of resistive switching in thin silicon carbon films in crossbar structures with metal electrodes was studied.

Multilayer metallic nanostructures are promising not only for the creation of spin valves based on the giant magnetoresistance effect, but also for studying the nature of topological magnetism aiming to creation, for example, new nanoscale devices for storing and transmitting data based on magnetic skyrmions. Actual problem remains the development of methods for the synthesis and configuration of thin-film nanostructures and control over spin textures in them under the influence of electric and spin currents arising due to the spin Hall effect, with external fields applied. In this work the metallic thin film nanostuctures of the ferromagnetic/heavy metal type were obtained by the magnetron sputtering method: Ru(10 nm)/Co(0.8)/Ru(2), Ru(10)/Co(0.8)/Ru(2)/W(4), Pt(5)/Co(0.8)/MgO(2)/Pt(2), Pt(15)/Co(0.8)/MgO(2)/Pt(2). Electrical contacts and Hall structures with different widths of the current-carrying bridge were fabricated on the obtained samples using electron beam and photolithography. Based on experimental data obtained from a vibrating magnetometer, the magnetic parameters of each sample were calculated, including saturation magnetization, energy and field of magnetic anisotropy, and coercive force, depending on the type of ferromagnetic layer and heavy metal layer. The domain structure of the samples was determined using Kerr microscopy. Electrical resistance modeling was performed, and critical current values and maximum current density in nanostuctures were estimated. It was shown that all obtained thin-film samples have perpendicular magnetic anisotropy and can be used to study current-induced phenomena and spin transfer processes in nanostuctures.

The strength and thermoelectric properties of PbTe and Sn_0.9Pb_0.1Te medium-temperature polycrystalline specimens with p and n conductivity types, respectively, have been studied. The specimens have been produced using extrusion and spark plasma sintering. The strength parameters of the materials were studied using uniaxial compression at 20 to 500 °C. The structure of the materials was studied using X-ray diffraction and electron microscopy. The electrical conductivity and the Seebeck coefficient were measured simultaneously using the four-probe and differential methods. The temperature conductivity and the specific heat capacity were measured using the laser flash and differential scanning calorimetry methods.

The PbTe and Sn_0.9Pb_0.1Te materials produced using extrusion and spark plasma sintering prove to be single-phase and have homogeneous compositions. For comparable synthesis methods, the dislocation density in the Sn_0.9Pb_0.1Te specimens is by an order of magnitude lower than in the PbTe ones.

Study of the mechanical properties of n and p conductivity type specimens over a wide temperature range from 20 to 500 °C has shown that their deformation is plastic and has no traces of brittle fracture. For these plastic materials, the strength criterion has been accepted to be the arbitrary yield stress corresponding to the stress at a 0.2% deformation. The 20 °C yield stress of PbTe and Sn_0.9Pb_0.1Te is far higher for the specimens produced by extrusion. For all the test temperatures and synthesis methods the Sn_0.9Pb_0.1Te specimens have a higher strength than the PbTe ones.

The PbTe and Sn_0.9Pb_0.1Te specimens produced by extrusion have better thermoelectric properties than the spark plasma sintered ones. The heat conductivity of the PbTe and Sn_0.9Pb_0.1Te specimens is almost the same regardless of compaction method.

InSb single crystals doped with tellurium have been grown by the modernised Czochralskii method in crystallographic directions [100], [111] and [112]. The development of channel inhomogeneity due to low activation energy of Te atoms capture by planes with high reticular density {111} in the process of crystal growth has been investigated. Based on the Hall method, it was shown that the electrophysical parameters, i.e., the concentration of free charge carriers and their mobility, in and outside the channel region differ from each other by 10 and 22%, respectively. It is shown that in addition to the crystallographic direction of growth, the development of channel inhomogeneity is greatly influenced by the selection of technological conditions (rotation speed of the seed, crucible with melt, its burial, etc.), as well as the design of the thermal unit of the growth furnace. It is revealed that to obtain InSb (111) wafers, which are in demand in the microelectronics market, the optimal technological solution is the development of single crystal growth mode, which allows to ensure early exit of channel inhomogeneity to the periphery. It is shown that by adding additional screens to the thermal unit of the growth furnace, thereby lowering the axial gradient at the crystallisation front, it is possible to achieve the channel exit to the single crystal diameter 4 cm earlier than the reverse cone.

The work is devoted to the preparation of a composite system consisting of thin ferromagnetic films Y₃Fe₅O₁₂ and ferroelectric Ba_0.8Sr_0.2TiO₃ on silicon substrates. Films were obtained by ion-beam deposition and high-frequency sputtering. To coordinate parameters of crystal lattices and thermal expansion coefficients, as well as to prevent chemical interaction of film and substrate materials, a buffer layer of TiO₂ titanium dioxide (one of oxides of the initial composition of the target) is used, parameters of which are in good agreement with the lattice of strontium barium titanate. The composition, structure and microstructural properties of films are investigated. The possibility of application is shown not only in microelectronics, but most of all in microelectromechanics, especially for the production of ferroelectric membranes on silicon integrated into the devices of microsystem technology.