Transition metal, boride and oxide doped Fe/MgB2 tapes and wires

•Bing Liu, Sonja Schlachter, Bernhard Obst und Wilfried Goldacker
Forschungszentrum Karlsruhe ITP 76021 Karlsruhe,P.O. Box 3640

Transition metal, boride and oxide doped mono- and multifilamentary Fe/MgB2 tapes and wires have been prepared by the powder-in-tube technique at ambient pressure from different precursors. For each composition,the heating process has been optimized to the full extent ac-cording to DTA measurements. We determined Tc and the transport critical current density in magnetic fields up to 9T and investigated the microstructure with high resolution SEM and quantitative EDX analysis.Compared with undoped samples, Jc and Hirr of doped samples have been enhanced significantly in high fields by effective pinning centers and improved grain connection due to sintering aid effect from the additives, with the highest Jc value over 5000A/cm2 at 4.2K/9T and insignificant Tc suppression. However, the improvement of thermal and mechanical stability of Fe/MgB2 tapes and wires remains a challenge for the future