PROTON IRRADIATION EFFECTS ON CRITICAL-CURRENT OF BULK SINGLE-CRYSTALSUPERCONDUCTING YBCO WIRE

We have investigated the effects of 10 MeV proton irradiation on the m agnetization M and critical current density J(c) of bulk single-crysta l YBa2Cu3O7-delta (YBCO) superconducting thick wire filaments produced through laser-heated floating zone (LHFZ) technique. M and J(c) were determined both along the length and perpendicular to the length of th e wire. Radiation-induced enhancement of J(c) along the length of the wire was observed while there was a small decrease in J(c) perpendicul ar to to its length. J(c) values along the length of the wire up to si milar to 1.4x10(5) A/cm(2) at 77K and similar to 1.3x10(6) A/cm(2) at 30K and in applied magnetic field H = 1 T were observed in the irradia ted samples. In the unirradiated sample, the difference in magnetizati on Delta M at a given field in the magnetic hysteresis loop for increa sing and decreasing field applied perpendicular to to the sample lengt h was observed to depend on the orientation of the sample about its ax is. This indicates anisotropy in J(c) along the sample length. This an isotropy increased on irradiation relative to the direction of irradia tion. We believe that these J(c) values along the length are amongst t he highest published J(c) values for bulk high temperature superconduc tor(HTS) thick wire filament.