Pinning mechanisms in niobium, irradiated by helium ions

Based on investigations of the structure and superconducting properties of specimens of Nb foils, implanted with different doses of high-energy He ions, pinning mechanisms acting in the specimens investigated are examined. The features of the dependences of the pinning force on the magnetic field, the angle which it forms with the surface of the specimen, the irradiation dose and temperature, including the nature of the sum of the elementary forces and the appreciable deviations from the scaling law are interpreted as the manifestation of two pinning mechanisms: on the external surface of the specimens and on dislocation loops, created by irradiation