Different high-Tc superconducting Y-Ba-Cu-O samples of slabs and rings have been
investigated. Using differently prepared Y1Ba2Cu3O7-d materials, significant deviations between
irradiated and unirradiated specimens have been detected in their properties. These investigations
demonstrate that unlikely prepared superconductors are differently sensitive to the external
irradiation, although they have the same composition. The irradiation applied during these
experiments consisted of high-energy Bi-ions with the flux of 5x1010 ions/cm2 and with the energy
of 720 MeV. As is experienced, a considerable variation of the magnetic moment in the extent of
19-44% and a significant increase of the critical current density up to 41% can be detected. These
originate from the change of the properties of materials due to the irradiation. For the evaluation of
the experiments a new fitting method is elaborated for the temperature dependence of the critical
current density, providing fully correct results for the whole temperature interval. The A.C.
magnetic measurements show, that the irradiation causes to reach the state of the perfect
diamagnetism at higher temperatures, than in the case of unirradiated samples. Similarly, the
irradiated specimens have much lower losses, than the unirradiated ones and even these smaller
values disappear at low temperatures.
