Critical current in V3Si monocrystals

The paper deals with studying the critical current in V3Si compounds in a wide range of temperature and magnetic fields. Samples were cut out of a monocrystal grown by a zone melting. They were etched for revealing the dislocation density after electropolishing. The cross section of samples with axes (100) and (110) was triangular. The magnetic field was (up to 150 kOe). Volt-ampere characteristics (VAC) were taken by the four-contact technique. The measurements showed that maxima in the oreintation dependence of the critical current arise when field directions are close to the (100) and (110) directions. The VAC show a distinct maximum at 4,2 K, and then voltage drops to zero. Hystersis is observed in VAC at temperatures close to that of transition to a superconducting state (16,45 K). Possible centers of pinning in V3Si are discussed. Qualitative explanation of VAC is given in the framework of the vortex-lattice dislocation model. Anisotropy of VAC is explained by the anisotropic character of the pinning-centers position which retard the dipole motion in the vortex lattice