The effect of ZrSi2 and SiC doping on the microstructure andJc–B properties ofPIT processed MgB2 tapes

Abstract

We investigated the effect of ZrSi2 and SiC doping on the microstructure, critical current densityJc and flux pinningof Fe-sheathed MgB2 tapes prepared by the in situ powder-in-tube method. Heat treatment was performed at a low temperatureof 650 °C for 1 h. The phases, microstructures and flux pinning were characterized by means of x-raydiffraction, scanning electron microscope, magnetic and transport property measurements. It wasfound that the tapes doped with nanoscale SiC had the best pinning performance, while theZrSi2 powder showed a similar improved field dependence ofJc compared withundoped samples. Jc values for the SiC doped samples were enhanced by two orders ofmagnitude at 4.2 K in magnetic fields above 8 T. At 4.2 K and 10 T, theJc reached ∼1.5 × 104 A cm−2. Moreover, the critical temperature for the doped tapes decreased slightly(<1.2 K). Microstructural analysis shows that very good grain connections or/and grainrefinement were obtained for the doped tapes. The mechanism of the enhancement of theflux pinning is also discussed.