For an epitaxial film of an electron-doped superconductor Nd(2-x)CexCuO4 (x=0.145), in a mixed state, a well-defined step structure is observed on the dependence of the c-axis flux-flow resistance on the magnetic field parralel to CuO2 layers. It is shown that in the region of a free flow of Josephson vortices, the structure is periodic with a period of deltaB~Phi0/(lambdaablambdac). It is essential that the magnetic penetration depths in the ab-plane (lambdaab) and along the c-axis (lambdac) determine the sizes of the Josephson vortices in the Lawrence-Doniach model for an anisotropic layered superconductor.

We report a brief overview of a number of results on a type of pairing state symmetry in cuprate HTSC from a current literature. The results of recent high-precision measurements of near-nodal d-type gap functions by a modern laser-based ARPES method or by a c-axis twisted Josephson junction for hole doped Bi-2212 system are presented. Recent experimental evidence in favor of d-type pairing symmetry, with a special nonmonotonic functional form, for electron doped cuprate NdCeCuO is discussed. A new essential result on the identification of d_x^2 - y^2 symmetry of superconducting order parameter for parent high-Tc cuprate structure, electron doped infinite layer SrLaCuO system, by the phase sensitive tests is described. A complex of the data presented indicates a vital role of d-wave pairing symmetry, in the special d_x^2 - y^2 form, for high-temperature conductivity in cuprate systems.

A brief review of the galvanomagnetic properties of highly anisotropic cuprate superconductors is presented, with an emphasis on the internal Josephson effect, which naturally exists in multilayer HTSC crystals. The transport of charge carriers perpendicular to the layers in such materials occurs by successive tunneling of quasiparticles (or Cooper pairs) between highly conducting (or superconducting) CuO2, layers through intermediate buffer layers. Currently available results on the nonmetallic conductivity along the c-axis in the normal state are analyzed, as are data on the distinctive branched current-voltage characteristics in the superconducting state, which are clear experimental manifestations of tunneling effects in layered cuprate superconductors.

The results of the measurements of electrical and Hall resistivities on polycrystalline PbS films doped with iodine obtained through hydrochemical deposition are presented. The analysis of the temperature dependence of resistivity points out the crossover from the hopping mechanism due to thermal delocalization in the impurity band to the variable range hopping mechanism. The increase in the iodine content in the films leads to an increase in the impurity ionization energy. It has been established that the temperature dependence of resistivity over a wide temperature range obeys the inverse Arrhenius law, which is characteristic of disordered polycrystalline films with different sizes and orientations of crystallites relative to the substrate, as confirmed by AFM topography, Raman spectra and X-ray diffraction measurements. We found that the type of charge carrier changes from electrons to holes with an increase in the iodine content. Additionally, for a wide range of iodine doping, the concentration of charge carriers is low, indicating the possible occurrence of a self-compensation mechanism due to the formation of impurity defects.

The current-voltage (I-V) properties along the c axis on Nd2-xCexCuO4/SrTiO3 epitaxial films with x = 0.145, 0.15 were investigated. For all the samples it has been established that the I-V characteristics exhibit several resistive branches, which correspond to the resistive states of individual Josephson junctions. The results confirm the idea of a tunneling mechanism between the CuO2 layers (superconductor - insulator - superconductor junction) for the investigated Nd2-xCexCuO4 compound. The I-V dependence of this compound with x = 0.15 points out on the nonmonotonic nature of the d-wave or anisotropic s-wave symmetry order parameter associated with the coexistence of superconductivity and antiferromagnetic fluctuations.

The mass magnetic susceptibility and resistivity of epitaxial films with different orientations of the c - axis of electron-doped Nd2-xCexCuO4+delta/SrTiO3 at different cerium concentrations and oxygen content were investigated. It was found the strong anisotropy of resistivity and the mass magnetic susceptibility at H = 100 Oe that is associated with the appearance of excess oxygen atoms between the conducting planes CuO2. An increase in the content of nonstoichiometric oxygen leads to an increase in the mass magnetic susceptibility and the destruction of the superconducting state.

A brief review of the transport and galvanomagnetic properties of an electron-doped Nd 2 – x Ce x CuO 4 layered superconductor with an emphasis on the role of the structure of Josephson vortices formed in the crystal in a magnetic field oriented in the parallel direction to the CuO 2 planes is given. The experimental data on the longitudinal and Hall magnetoresistance of the recently synthesized Nd 2 – x Ce x CuO 4 /SrTiO 3 epitaxial films are analyzed. The possibility of formation of a system of Josephson vortices in this highly anisotropic system is determined by the unique orientation of the c axis and the conducting CuO 2 planes of the Nd 2 – x Ce x CuO 4 compound with respect to the substrate plane.

Hybrid metal-organic CH3NH3PbI3 perovskites are promising materials for photovoltaics and optoelectronics, and the recently discovered magnetic and electrical ordering in them stimulates their potential applications in spintronics. The temperature (in the range of 5–300 K) and magnetic field (up to 50 kOe) dependences of the magnetization of CH3NH3PbI3 single crystals for different directions of the magnetic field are measured. A strong anisotropy of the magnetic properties is found. If the magnetic field is perpendicular to the (001) crystallographic plane, the diamagnetic behavior of the magnetization is observed. If the field is oriented in the (001) plane, a transition from the ferromagnetic state to the paramagnetic state is revealed at a temperature of about 115 K. The features of the magnetic susceptibility observed in the low-temperature range are characteristic of the presence of antiferromagnetic correlations. In addition, in the CH3NH3PbI3 hybrid perovskite, a relation between the magnetic properties and the structural phase transition from the tetragonal to the orthorhombic phase is determined. The effective magnetic moment equals 0.76μB and 0.39μB in the tetragonal and orthorhombic phases, respectively.

This paper presents the results of studies of the temperature and field dependences of the resistivity tensor of the electron-doped superconductor Nd2 –xCexCuO4 (0.12 ≤ x ≤ 0.20) in the CuO2 conducting planes and in the direction perpendicular to the CuO2 planes. These results are successfully interpreted within the concept of quasi-two-dimensionality of the systems with high metallic conductivity in the CuO2 conducting planes (dρab/dT > 0) and nonmetallic temperature dependence of conductivity in the direction of the c‑axis (dρc/dT < 0) due to incoherent tunneling and thermal activation through barriers between the CuO2 conducting layers. The specificities of the behavior of the magnetoresistivity ρxx(B) and the Hall resistivity ρxy(B) in the mixed (resistive) state are associated with the dynamics of the transverse motion of Abrikosov and Josephson vortices in the flux flow regime in crossed electric and magnetic fields.

The magnetic susceptibility in the high-quality epitaxial films Nd1.82Ce0.18CuO4/SrTiO3 with different orientation of the c-axis of electron-doped superconductors Nd1.82Ce0.18CuO4 was investigated. The strong anisotropic behavior of the magnetic susceptibility versus external magnetic field chi(parallel to)(H) and chi(perpendicular to)(H) at H<10 kOe and highly anisotropic temperature dependencies of the magnetic susceptibility chi(parallel to)(T) and chi(perpendicular to)(T) at low magnetic field H = 100 Oe is associated with different magnetic ordering of Nd3+ (Ce4+) rare earth magnetic ions and copper ions at different orientations of the external magnetic field with respect to the conducting planes of CuO2. The presence of the residual short ranged antiferromagnetic ordering of copper ions even in the overdoped region leads to magnetic anisotropy in the conducting planes.

The carrier transport and the motion of a vortex system in a mixed state of an electron-doped high-temperature superconductors Nd2-xCexCuO4 were investigated. To study the anisotropy of galvanomagnetic effects of highly layered NdCeCuO system we have synthesized Nd2-xCexCuO4/SrTiO3 epitaxial films with non-standart orientations of the c-axis and conductive CuO2 layers relative to the substrate. The variation ofe the angle of inclination of the magnetic field B, relative to the current J, reveals that the behavior of both the in-plane r_xx(B) and the out-plane r_xy(B) resistivities in the mixed state is mainly determined by the perpendicular to J component of B, that indicates the crucial role of the Lorentz force F_L~[JxB] and defines the motion of Josephson vortices across the CuO2 layers.

Dielectric and magnetic properties of the Nd2 – xCexCuO4 + δ bulk single crystal with x = 0.1 are studied in this work. The anisotropy of the field and temperature dependences of the specific magnetization is found. The value of specific magnetization measured in the magnetic field applied in parallel to CuO2 planes is higher than that measured in the magnetic field applied perpendicular to the planes; this is related to the additional contribution of magnetic moments of neodymium ions. In this case, at temperatures T < 100 K, when the magnetic field H is perpendicular to CuO2 planes, an area of antiferromagnetic coupling of ions exists within the CuO2 planes, which is not observed in the case of the parallel orientation of the magnetic field with respect to the CuO2 planes. Microwave studies show the existence of strong permittivity dispersion, which indicates the presence of natural resonance frequency, whose value is beyond the frequency range of performed measurements.

The mass magnetization and the magnetic susceptibility of underdoped epitaxial films Nd2-xCexCuO4 + delta/SrTiO(3)with different orientation of thec-axis of Nd(2-x)Ce(x)CuO(4 + delta)compounds relatively to the substrate withx = 0 and 0.12 (optimal annealing) andx = 0.135 and 0.145 (as grown) were investigated. It was shown that as grown state is not superconducting at any magnetic field orientation and the optimal annealing of the heavily underdoped film withx = 0.12 leads to the manifestation of latent superconductivity. The biggest mass magnetization and susceptibility in the normal state at 4.2 K and 77 K for epitaxial films Nd2-xCexCuO4 + delta/SrTiO(3)withH perpendicular to cwere found.

The carrier transport and the motion of a vortex system in the electron-doped high-temperature superconductors Nd2-xCexCuO4 in underdoped and optimally doped (x = 0135, 0.145, 0.15) regions, in the area of the evolution from antiferromagnetic to superconducting order were investigated. To study the anisotropy of the transport properties of highly layered NdCeCuO system we have synthesized Nd2-xCexCuO4/SrTiO3 epitaxial films of three types with different orientations of the c-axis and conductive CuO2 layers relative to the substrate. Such a set of samples allowed us to study the processes of both standard (in the CuO2 layers) and lateral (across the CuO2 layers) carrier transfer in the normal and the mixed states of a superconductor. In a flux-flow regime, in magnetic field B, the dynamics of Abrikosov (B||c-axis) and Josephson (B||ab-plane) vortices are thoroughly investigated and analyzed which is perspective for scientific purposes and for practical applications in measurement technology.

The mass magnetization and the magnetic susceptibility of underdoped epitaxial films Nd 2- x Ce x CuO 4 + δ /SrTiO 3 with different orientation of the c -axis of Nd 2- x Ce x CuO 4 + δ compounds relatively to the substrate with x = 0 and 0.12 (optimal annealing) and x = 0.135 and 0.145 (as grown) were investigated. It was shown that as grown state is not superconducting at any magnetic field orientation and the optimal annealing of the heavily underdoped film with x = 0.12 leads to the manifestation of latent superconductivity. The biggest mass magnetization and susceptibility in the normal state at 4.2 K and 77 K for epitaxial films Nd 2- x Ce x CuO 4 + δ /SrTiO 3 with H ⊥ c were found.

The results of studying the conductivity and critical current density in monocrystalline Nd2–xCexCuO4+δ/SrTiO3 (x = 0.15; 0.17) films with c-axis perpendicular or parallel to the substrate plane are presented. It is found that in stoichiometrically annealed films with the optimum cerium content (x = 0.15) the resistance anisotropy is maximal and the anisotropy of the critical current density is jcab/jcc ≅ 3 · 103 at T = 4.2 K. The strong anisotropy of the critical current density is considered in the framework of natural superlattices, with alternating conductive CuO2 and non-conducting buffer Nd(Ce)O layers. It is shown that the high density of the critical current along the conductive CuO2 planes is caused by the pinning of vortices on the buffer layers, whereas the strong anisotropy of the critical current is caused by the anisotropic motion of the vortex lattice in the layered superconductor.

In this paper we present the experimental results on the temperature dependences of c-axis resistivity, rho(c)(T), for epitaxial films of n-type superconductor Nd2-xCexCuO4+delta deposited on (110) SrTiO3 single crystal substrate in a wide range of Ce content from lightly to heavily substitution regions (x = 0.12 - 0.20) under an optimal annealing. Alternative empirical models were used for a description of the observed semiconductor-like rho(c)(T) dependence. An excellent quantitative depiction of the experimental rho(c)(T) dependences turned out to be possible for all investigated samples in a model of natural superlattice with temperature - dependent barrier height.

The in-plane and out-of-plane carrier transport and the motion of a vortex system in the high quality epitaxial films with different orientation of the c axis of electron-doped superconductors Nd-2-xCexCuO4+delta d in crossed magnetic and electrical fields were investigated. The activated behavior of the vortex through the barrier at low temperature between CuO2 - planes due to intrinsic interlayer pinning is found as a function of the magnetic field depending on the anisotropy resistivity coefficient.