The crystal structure of the manganite Nd0.5Sr0.5MnO3 is studied at temperature T=300 and 77.3 K by means of an x-ray diffractometer. It is shown that the transition from the ferromagnetic metallic state to the antiferromagnetic insulating charge-ordered state is accompanied by a lowering of the symmetry of the structure from orthorhombic to monoclinic. The space-group symmetry of the orthorhombic and monoclinic phases is identified as Imma and P21/m, respectively. Twinning of the crystal and the formation of a twin domain structure with coherent boundaries in the (00l) crystallographic planes are found.

Torque measurements were performed on a high-quality single crystal of the uniaxial superconductor 2H-NbSe 2 in a tilted magnetic field 0-200 kG, in the temperature range 1.5-4.2 K. The transverse component of the absolute magnetization was derived in a magnetic field directed at an angle of 77°to the axis of anisotropy, and its field dependence was analyzed in a reversible domain of the mixed state. The penetration depth and anisotropy characteristics were obtained for the sample under study.

The results of a comparative study of the oscillating magnetostriction and absolute magnetization components in the single crystal of the layered superconducting compound 2H-NbSe2 are presented. The measurements were made in the temperature range 1.5–8 K in a magnetic field of 0–20 T with in-plane orientation (normal to the hexagonal axis). The mechanical stress derivative of the extremal cross-sectional area of the Fermi surface is derived from a thermodynamic analysis. The values obtained are considerably higher, by an order of magnitude, than those for other metals, which explains the observed enhancement of the magnetostriction oscillations in comparison with the magnetization oscillations.