High critical currents under magnetic field at 77K for large size textured YBaCuO samples

The transport critical current of large size textured YBaCuO samples (90 mm length, 130 mm(2) section) has been measured at 77K under external magnetic field (up to 5T). These samples have been textured under thermal gradient. The samples were prepared starting from 1/2/3 powder mixed with 10 wt% silver. After shaping and sintering by usual ceramic process, they have been moved across the furnace thermal gradient. All characterizations have been performed on the rough samples. Their microstructure shows large unidirectionaly textured domains. The transport critical currents at 77K, Ic, for a usual 1 mu V/cm criterion, hit 1160A at 1T and 928A at 5T (the corresponding transport critical current densities, Jc, are 9A/mm(2) at 1T and 7A/mm(2) at 5T. In any case, Jc does not constitute the critical propertie for most of 77K electrical engineering applications). To our knowledge, these values of Ic constitute to date the best results at 1 mu V/cm criterion for YBaCuO samples of such geometry. Considering their sizes and outstanding electrical achievements, these samples might be used as current lead for 4,2K operating systems.