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The influence of fast-electron irradiation on the properties of the hexagonal modification of niobium diselenide, 2H–NbSe2, is investigated by the methods of x-ray and electron diffractometry. The observed changes in the diffractograms are explained by a redistribution of the electron density under irradiation, viz., an increase of the electron density in the planes with high packing density—the basal and prismatic planes {110}, {210}. The appearance of diffuse scattering of x rays and electrons at high doses of irradiation is attributed to growth of the electron density of the Fermi liquid.

The anisotropic magnetic properties of the metallic layered compound with hexagonal crystal structure 2H-NbSe2 are investigated as a function of their dependence on high-energy electron irradiation. Pauli paramagnetism of free electrons is shown to dominate the magnetic susceptibility, P. The anisotropy is related to spin-orbit effects on the hybridized electronic states. Irradiation affects the density of states at the Fermi surface, increasing both P and the anisotropy. Below a threshold temperature, TS=54 K, the paramagnetic contribution, which increases with the dose, is ascribed to dangling bonds, nanotubes and nanorods generated by irradiation.

An x-ray diffraction analysis of the compound EuBa2Cu3O7−δ is carried out in the temperature range 20–300K. At all temperatures of measurement the structure is described in the orthorhombic system. Nonmonotonic growth of the crystal lattice parameter c with decreasing temperature is observed in the interval 150–20K, and substantial features of the temperature dependence of the coefficient of linear thermal expansion appear below the Debye temperature. The results of the experiment are in complete agreement with the conclusions of a microscopic treatment of the vibrations of the atoms of the BaO and europium layers and also the Cu–O chains.

The intensity of x-ray scattering in the layered metal 2H‐NbSe2 has been investigated experimentally in the temperature range below the temperature of the transition into the charge-density wave state. It is shown that the relation I∼(TC−T)−γ with TC∼30K and γ=1.6±0.2, as is characteristic for quasi-elastic (quasi-Bragg) scattering, describes the scattering intensity. Such scattering is strong when the width ΔeXR of the spectral distribution of the x-ray radiation is greater than the spectral width of the fluctuations Δef of the order parameter. The inequality Δef

Single crystals of layered niobium diselenide (2H‐NbSe2) compound with hexagonally packed layers were studied in a range of temperature 1.5–300 K by measuring magnetostricrtion and magnetization in field up to 20 T. The data are compared with magnetic susceptibility measurements. Specific features of measured temperature and field dependences were observed near CDW transition temperature (32.5 K) and superconducting transition (7.2 K), sensitive to magnetic field direction and strength.

Variation of crystal‐lattice parameters with temperature was studied by means of X‐ray diffraction technique on the perovskite‐like structures with Ba‐ substitution for light rare earth. Anisotropic negative thermal expansion was observed and explained within the “membrane effect” model proving its lattice origin.