Enhancements of the critical currents of YBaCuO single crystals by neutron (n) and proton (p) irradiation

摘要

We present results of magnetization hysteresis and (Tc) measurements of neutron and proton irradiated YBaCuO single crystals. The crystals used for comparison were irradiated to a fluence of 2(times)10(sup 7)n/cm(sup 2) (n,E (gt) 0.1MeV) and 1(times)10(sup 16)p/cm(sup 2) (p,E=3.5MeV). The critical currents at 1T and 10K are enhanced by a factor of 5 for the neutron irradiated and a factor of 9 for the proton irradiated sample respectively. After irradiation the crystals were annealed at 100, 200 and 300C for 8h each in air. Following each annealing step the critical temperature and the magnetization hysteresis at 10 and 70K was measured. Upon annealing, we observe a decrease of the critical currents, which is more pronounced for the proton irradiated sample. This decrease is related to the removal of point defects or their small clusters. Thus, their contribution to pinning can be studied. The critical temperature decreases after both types of irradiation by about 0.5K and is fully recovered after annealing.