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INTRODUCTION. The article presents the evolution of legal regulation of the institution of enhanced cooperation as a legal form of flexible integration in European Union (EU) law. Flexible integration is a fairly widespread and objectively existing legal phenomenon in the practice of various integration associations. However, it is within the framework of EU law that the concept of enhanced cooperation has received the greatest development and legal regulation. This was largely due to the EU's desire to regularize and subordinate alternative forms of co natural that interstate cooperation within the framework of one or another integration cooperation acquires more and more complex character, and cooperation of the member states of an integration association within the framework of one or another direction of interaction has uneven and heterogeneous character. MATERIALS AND METHODS. The methodological basis of the study was traditional general scientific and special methods of cognition of legal phenomena: comparative legal method; method of scientific analysis; formal legal method; method of synthesis of social and legal phenomena.RESEARCH RESULTS. As a result of the analysis, the main stages of development of prerequisites and reasons for the legal regulation of enhanced cooperation have been identified and the periodization of the development of legal regulation of this institution has been proposed. DISCUSSION AND CONCLUSIONS. Within the framework of the proposals on the periodization of the development of legal regulation of the institution of enhanced cooperation the following stages can be distinguished. The first stage can be labeled as “pre-Amsterdam”. This period is characterized by the formation of conceptual foundations of enhanced cooperation as a legal form of flexible integration. Within the framework of the “pre-Amsterdam” period there is an application of some form of flexible integration (Schengen, euro zone, etc.). The conceptualization of enhanced cooperation as a form of flexible integration was the basis for the normative-legal consolidation of this institution in the founding treaties of the EU. The next stage can be called “Amsterdam-Nicean”. Although the institution of enhanced cooperation received different names in the Amsterdam and Nice versions of the establishing treaties, it seems possible to unite this period into one: despite the normative-legal consolidation of enhanced cooperation as a form of flexible integration, the relevant norms of the establishing treaties have not actually received practical application. Finally, the next stage – the “Lisbon” period is characterized by the active ap[1]plication of the norms of the establishing treaties in the EU practice, including judicial.

Abstract Magnetic topological insulators (TIs) herald a wealth of applications in spin‐based technologies, relying on the novel quantum phenomena provided by their topological properties. Particularly promising is the (MnBi2Te4)(Bi2Te3)n layered family of established intrinsic magnetic TIs that can flexibly realize various magnetic orders and topological states. High tunability of this material platform is enabled by manganese–pnictogen intermixing, whose amounts and distribution patterns are controlled by synthetic conditions. Here, nuclear magnetic resonance and muon spin spectroscopy, sensitive local probe techniques, are employed to scrutinize the impact of the intermixing on the magnetic properties of (MnBi2Te4)(Bi2Te3)n and MnSb2Te4. The measurements not only confirm the opposite alignment between the Mn magnetic moments on native sites and antisites in the ground state of MnSb2Te4, but for the first time directly show the same alignment in (MnBi2Te4)(Bi2Te3)n with n = 0, 1 and 2. Moreover, for all compounds, the static magnetic moment of the Mn antisite sublattice is found to disappear well below the intrinsic magnetic transition temperature, leaving a homogeneous magnetic structure undisturbed by the intermixing. The findings provide a microscopic understanding of the crucial role played by Mn–Bi intermixing in (MnBi2Te4)(Bi2Te3)n and offer pathways to optimizing the magnetic gap in its surface states.

Magnetic topological insulators (TIs) herald a wealth of applications in spin‐based technologies, relying on the novel quantum phenomena provided by their topological properties. Particularly promising is the (MnBi2Te4)(Bi2Te3)n layered family of established intrinsic magnetic TIs that can flexibly realize various magnetic orders and topological states. High tunability of this material platform is enabled by manganese–pnictogen intermixing, whose amounts and distribution patterns are controlled by synthetic conditions. Here, nuclear magnetic resonance and muon spin spectroscopy, sensitive local probe techniques, are employed to scrutinize the impact of the intermixing on the magnetic properties of (MnBi2Te4)(Bi2Te3)n and MnSb2Te4. The measurements not only confirm the opposite alignment between the Mn magnetic moments on native sites and antisites in the ground state of MnSb2Te4, but for the first time directly show the same alignment in (MnBi2Te4)(Bi2Te3)n with n = 0, 1 and 2. Moreover, for all compounds, the static magnetic moment of the Mn antisite sublattice is found to disappear well below the intrinsic magnetic transition temperature, leaving a homogeneous magnetic structure undisturbed by the intermixing. The findings provide a microscopic understanding of the crucial role played by Mn–Bi intermixing in (MnBi2Te4)(Bi2Te3)n and offer pathways to optimizing the magnetic gap in its surface states. [ABSTRACT FROM AUTHOR]

Abstract We study the surface crystalline and electronic structures of the antiferromagnetic topological insulator MnBi2Te4 using scanning tunneling microscopy/spectroscopy (STM/S), micro(μ)-laser angle-resolved photoemission spectroscopy (ARPES), and density functional theory calculations. Our STM images reveal native point defects at the surface that we identify as BiTe antisites and MnBi substitutions. Bulk X-ray diffraction further evidences the presence of the Mn-Bi intermixing. Overall, our characterizations suggest that the defects concentration is nonuniform within crystals and differs from sample to sample. Consistently, the ARPES and STS experiments reveal that the Dirac point gap of the topological surface state is different for different samples and sample cleavages, respectively. Our calculations show that the antiparallel alignment of the MnBi moments with respect to those of the Mn layer can indeed cause a strong reduction of the Dirac point gap size. The present study provides important insights into a highly debated issue of the MnBi2Te4 Dirac point gap.

Iron deficiency with or without anemia in pregnant women is quite common today. In fact, anemia affects nearly 30% of women of reproductive age, and its prevalence among pregnant women is estimated to be 38% worldwide. Although iron deficiency (IR) is not the only cause of anemia, it is the most prevalent one. Anemia-reduction strategies among pregnant women are often ineffective, and severe anemia can greatly increase the risk of maternal mortality, as reported by WHO. Now therefore, the current guidelines for screening and treatment of ID-anemia (IDA) in pregnant women and new-borns require change. Severe anemia can greatly increase the risk of maternal death and adversely affect a developing fetus and new-born. In this review, we analyse the available data on the epidemiology and the effects of iron deficiency on mothers and infants, current treatment strategies and screening recommendations, as well as examine the treatment of IDA in pregnant women and newborns and the problem of poor compliance in patients with latent iron deficiency. A continuous long-term course of administration of oral iron supplements is one of the components of success in the treatment of IDA, and particularly latent forms of iron deficiency in pregnant women. It is often the case that poor patients’ compliance with therapy leads to poor treatment outcomes and misleading conclusions about the ineffectiveness of oral iron dosage forms in the battle against IDA. The data we have analysed suggest the possibility of increasing compliance with IDA treatment in pregnant women.

A single crystalline layered semiconductor In1.2Ga0.8S3 phase was grown, and by intercalating p-aminopyridine (NH2-C5H4N or p-AP) molecules into this crystal, a new intercalation compound, In1.2Ga0.8S3·0.5(NH2-C5H4N), was synthesized. Further, by substituting p-AP molecules with p-ethylenediamine (NH2-CH2-CH2-NH2 or p-EDA) in this intercalation compound, another new intercalated compound—In1.2Ga0.8S3·0.5(NH2-CH2-CH2-NH2) was synthesized. It was found that the single crystallinity of the initial In1.2Ga0.8S3 samples was retained after their intercalation despite a strong deterioration in quality. The thermal peculiarities of both the intercalation and deintercalation of the title crystal were determined. Furthermore, the unit cell parameters of the intercalation compounds were determined from X-ray diffraction data (XRD). It was found that increasing the c parameter corresponded to the dimension of the intercalated molecule. In addition to the intercalation phases’ experimental characterization, the lattice dynamical properties and the electronic and bonding features of the stoichiometric GaInS3 were calculated using the Density Functional Theory within the Generalized Gradient Approximations (DFT-GGA). Nine Raman-active modes were observed and identified for this compound. The electronic gap was found to be an indirect one and the topological analysis of the electron density revealed that the interlayer bonding is rather weak, thus enabling the intercalation of organic molecules.

By using Differential Thermal Analysis (DTA) and Powder X-ray Diffraction (PXRD) techniques, the phase diagram of the MnTe-Sb2Te3 system has been constructed for the first time in the entire composition range. The system features two ternary layered van der Waals (vdW) compounds. Apart from known MnSb2Te4, novel MnSb4Te7 which a structural analogous of the known MnBi4Te7 was found in the system. Crystal structure parameters of both compounds were determined by Rietveld refinement using the fundamental parameter approach. Both compounds were found to decompose via peritectic reactions and possess significant homogeneity ranges. The title system is also characterized by the existence of the wide solid solution field based on the starting Sb2Te3. The present results would be useful for the bulk single crystal growth of both compounds from the liquid phase via the determination of primary crystallization areas.

Magnetic topological insulators are narrow-gap semiconductor materials that combine non-trivial band topology and magnetic order.sup.1. Unlike their nonmagnetic counterparts, magnetic topological insulators may have some of the surfaces gapped, which enables a number of exotic phenomena that have potential applications in spintronics.sup.1, such as the quantum anomalous Hall effect.sup.2 and chiral Majorana fermions.sup.3. So far, magnetic topological insulators have only been created by means of doping nonmagnetic topological insulators with 3d transition-metal elements; however, such an approach leads to strongly inhomogeneous magnetic.sup.4 and electronic.sup.5 properties of these materials, restricting the observation of important effects to very low temperatures.sup.2,3. An intrinsic magnetic topological insulator--a stoichiometric well ordered magnetic compound--could be an ideal solution to these problems, but no such material has been observed so far. Here we predict by ab initio calculations and further confirm using various experimental techniques the realization of an antiferromagnetic topological insulator in the layered van der Waals compound MnBi.sub.2Te.sub.4. The antiferromagnetic ordering that MnBi.sub.2Te.sub.4 shows makes it invariant with respect to the combination of the time-reversal and primitive-lattice translation symmetries, giving rise to a Z.sub.2 topological classification; Z.sub.2 = 1 for MnBi.sub.2Te.sub.4, confirming its topologically nontrivial nature. Our experiments indicate that the symmetry-breaking (0001) surface of MnBi.sub.2Te.sub.4 exhibits a large bandgap in the topological surface state. We expect this property to eventually enable the observation of a number of fundamental phenomena, among them quantized magnetoelectric coupling.sup.6-8 and axion electrodynamics.sup.9,10. Other exotic phenomena could become accessible at much higher temperatures than those reached so far, such as the quantum anomalous Hall effect.sup.2 and chiral Majorana fermions.sup.3. An intrinsic antiferromagnetic topological insulator, MnBi.sub.2Te.sub.4, is theoretically predicted and then realized experimentally, with implications for the study of exotic quantum phenomena., Author(s): M. M. Otrokov [sup.1] [sup.2] [sup.3] [sup.4] , I. I. Klimovskikh [sup.4] , H. Bentmann [sup.5] , D. Estyunin [sup.4] , A. Zeugner [sup.6] , Z. S. Aliev [sup.7] [...]

The phase equilibria in the MnGa2Tе4-MnIn2Tе4 system were experimentally investigated by means of differential thermal analysis and powder X-ray diffraction technique. It was found that this system is quasi-binary and characterized by dystectic and eutectic equilibria and the formation of a wide area of solid solutions based on the starting compounds. The crystal structures of the MnGaInTe4 and MnIn2Tе4 were refined by the Rietveld method using powder X-ray diffraction data. It was established, that both phases crystallize in the tetragonal system (Space group I-42m). Electron paramagnetic resonance and Raman spectra, as well as the temperature dependences of the electrical conductivity and the Hall effect for the MnGaInTe4 crystal, were studied.

The compounds of the MB2X4 type (M-Mn, Fe, Co, Ni, B-Ga, In, Sb, Bi; X- S, Se, Te) exhibit the phenomenon of electron- or optically-controlled magnetism; therefore, they are very promising for creation of lasers, modulators of light, photodetectors and other magnetic fi eld controllable functional devices. Recent studies have shown that the range of functional characteristics of these compounds can be substantially improved and expanded due the changing the composition of these compounds and the obtaining solid solutions of various types of substitution. The abovementioned shows the relevance of researches aimed to obtain and study the properties of solid solutions based on the MB2X4 compounds. The development and optimization of processes for the preparation of new complex phases are based on the data on phase equilibria and thermodynamic characteristics of the corresponding system. The aim of the present study was determining the phase relations in the FeGa2Se4-FeIn2Se4 system. We used the differential thermal analysis (DTA) and X-ray diffraction (XRD) in order to analyze the samples of the system. The temperatures of the thermal effects were determined using a NETZSCH 404 F1 Pegasus differential scanning calorimeter within room temperature and ~1300 K. The phase composition of the powdered samples was identifi ed by powder X-ray diffraction D2 Phaser diffractometer at room temperature. The defi nition and refi nement of the structure, as well as calculation of the unit cell parameters of intermediate alloys, were carried out by the Rietveld method using Topas-4.2 software. It is established that the studied system is quasi-binary, and characterized by the presence of the distectic and eutectic equilibria, as well as the formation of broad areas of solid solutions FeGa2Se4 (α-phase) and FeIn2Se4 (β-phase). β-phase with composition of FeGaInSe4 melts congruently at 1222 K and crystallizes in the trigoinal system: Sp.gr. R3m, а = 0.39290(1) nm, с = 3.8542(6) nm, V =515.28 (15) nm3. Using the powder diffraction data, the occupation of the crystallographic positions in FeGaInSe4 was determined by the Rietveld method. It was shown that the occupation of the crystallographic positions in FeGaInSe4 qualitatively differs from FeIn2Se4. Obtained experimental results can be used for choosing the composition of solution-melt for the growth of the high-quality crystals of intermediate phases which are of interest as magnetic semiconductors.