High critical transport currents of melt textured YBCO up to 6000 A

A melting zone processing has been developed to texture long bars of YBCO (10 cm length and 5 mm diameter). The misorientation of (a,b) planes with the sample long axis is weak, The transport current is produced by a capacitor discharge with period varying between 1.25 and 20 ms. Pulsed transport currents reaching 3000 A. (15000 A/cm(2)) and 6000 A (30000 A/cm(2)) could cross resistanceless samples at 77 K over several centimeters length. These results show that YBCO can transport high nominal currents even up to its critical current thanks to high quality of contacts. Above the critical current, the material has to be protected against the development of the magnetothermal transition.