We report comprehensive study of physical properties of the binary superconductor compound SnAs. The electronic band structure of SnAs was investigated using both angle-resolved photoemission spectroscopy (ARPES) in a wide binding energy range and density functional theory (DFT) within generalized gradient approximation (GGA). The DFT/GGA calculations were done including spin-orbit coupling for both bulk and (111) slab crystal structures. Comparison of the DFT/GGA band dispersions with ARPES data shows that (111) slab much better describes ARPES data than just bulk bands. Superconducting properties of SnAs were studied experimentally by specific heat, magnetic susceptibility, magnetotransport measurements and Andreev reflection spectroscopy. Temperature dependences of the superconducting gap and of the specific heat were found to be well consistent with those expected for the single band BCS superconductors with an isotropic s-wave order parameter. Despite spin-orbit coupling is present in SnAs, our data shows no signatures of a potential unconventional superconductivity, and the characteristic BCS ratio 2∆/Tc = 3.48 − 3.73 is very close to the BCS value in the weak coupling limit.

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It is proposed to use the HTSC quantum levitation phenomenon in magnetic fields of various configurations to develop the systems of contact-free positioning and transport of cryogenic fuel targets (CFTs) to the focus of a high-power laser installation or the IFE reactor. The results are presented of a large cycle of experimental studies using YBa 2 Cu 3 O 7−x superconducting ceramics and permanent magnet guideways based on various combinations of permanent magnets to develop "CFT-MAGLEV" delivery systems.Keywords: cryogenic fuel target, contact-free delivery, high-temperature superconductors, permanent magnet guideway (PMG) system.Introduction. The formation and delivery of cryogenic fuel targets (CFT) with high frequency is a necessary condition for developing a factory of targets to provide operation of the inertial fusion energy (IFE) reactor [1].The delivery feature is the requirements for the delivery frequency (1-10 Hz), delivery precision (±20 μm) and the delivery temperature mode. A cryogenic fuel target (a hollow polymeric shell with a spherical layer of hydrogen fuel on its inner surface ( Fig. 1(a)) should have a temperature no higher than 18.5 K at the instant of laser irradiation. At the same time, the temperature of the wall of the reactor chamber itself can reach significant values. For example, for the SOMBRERO reactor chamber, this value is 1758 K [2]. Furthermore, at the acceleration stage in the injector, CFT overloads can be from 500 to 1000 g. This is precisely why its motion should be in a special cylindrical carrier, i.e., a sabot ( Fig. 1(b)), which transfers the motion momentum to the CFT during its acceleration to required injection velocities (∼400 m/s). However, in this case, heat is released due to sabot friction with the injector directing tube wall. To exclude this source of fuel layer damage, it was proposed to use a superconductor sabot as a CFT carrier which excludes its contact with the injector directing tube. Thus, the development of the contact-free CFT positioning and transport system is one of the most important problems in the general ICF program. Since the CFT temperature at the instant of laser irradiation should be ∼18.5 K, type-I superconductors (low-temperature, with superconducting transition temperatures T C < 9 K) are inapplicable to solve the posed problem.Preliminary studies at the Lebedev Physical Institute using type-II superconductors, i.e., hightemperature superconductors (HTSC), confirmed the efficiency of this approach [3]. In this paper, we present the results of a new series of experiments on magnetic levitation (MAGLEV) of YBa 2 Cu 3 O 7−x superconducting ceramics samples.Fabrication technology of HTSC pellets and powders based on YBa 2 Cu 3 O 7−x superconducting ceramics. HTSC substrates were made based on superconducting ceramics at the Superconductivity Laboratory of the Lebedev Physical Institute. YBa 2 Cu 3 O 7−x superconducting ceramics with superconducting transition temperature T C = 91 K was prepared by the solid-phase reaction method. The lower

The effect of the boundary conditions for solutions on the Ginzburg-Landau (GL) equations for superconducting plates in the vortex-free limit is studied by numerical methods. Based on the self-consistent solution of the system of GL equations, the dependence of the critical current I c on the external magnetic field and the distribution of the order parameter over the plate thickness are determined. When solving the equations with general boundary conditions, it was found that the critical temperature and critical current density decreased in comparison with those obtained by solving equations with ordinary boundary conditions. According to the results of this study, the use of general boundary conditions leads to a number of interesting results which were not observed when using ordinary boundary conditions. The range of the applicability of the vortex-free limit for the films of thickness of the order of the coherence length ξ are discussed. The effect of boundary conditions on the applicability of this limit is analyzed.