IMPROVED FLUX-PINNING THROUGH CE-MG ADDITIONS IN MELT-TEXTURED YBA2CU3O7-DELTA

The effects of Ce-based additions (CeO2 and BaCeO3) in combination wit h MgO additions on the magnetic properties of melt textured YBa2Cu3O7- delta have been investigated. The additions lend to improvements in th e magnetic properties of YBa2Cu3O7-delta compared to samples with eith er addition alone or with no additions. The Ce-Mg addition combination produces a ''peak effect'' in the magnetic hysteresis loop without si gnificant T-c degradation. This is postulated to be due to the formati on of a new type of pinning center, Both Ce and Mg ions are thought to substitute in the YBa2Cu3O7-delta lattice, creating defects that prod uce a peak effect in the magnetic hysteresis loop. Mg additions alone lead to a reduced Tc, while Ce additions restore the Tc and enhance th e magnitude of the peak. (C) 1997 American Institute of Physics. [S000 3-6951(97)03051-9].