INFLUENCE OF PROTON-INDUCED DEFECTS ON TRANSPORT AND STRUCTURAL-PROPERTIES OF CERAMIC YBCO

Previous and recent results on transport properties of sintered YBCO b efore and after 6.5 MeV proton implantation are reported. The samples under study come from two different batches, processed by nominally id entical preparation methods. For the first batch, irradiation produces enhancement of the critical current density, while for the second one an average damage is observed. An SEM analysis of two different sampl es shows dissimilar pre-irradiation grain boundary structures. We infe r that these different structures are responsible for the dissimilar r esponse to the irradiation.