Characterization of YBCO coated conductors deposited by LPE on MgO substrates

Results on the field and temperature dependence of the critical transport current density in YBa 2 Cu 3 O 7−δ coated conductors of various thickness are presented. The conductors were deposited by liquid phase epitaxy on RE-123 buffer layers on MgO substrates. The analysis of the remanent fields in magnetization loops with different maximum external field provides information about the inter- and intragrain current distribution. From the reserve leg of the magnetization loops the average grain size in the YBCO layer can be estimated. The results of these magnetic measurements are compared to those obtained from magneto-optical imaging. Modifications of the defect structure by neutron irradiation are reported as well. The rssulting defects are either collision cascades, originating from fast neutrons (E > 0.1 MeV), or point defects, originating from neutrons with lower energies. Their influence on J c will be discussed.