Jc Enhancement in Nano-Si3N4 Doped MgB2/Fe Tapes Prepared by a Short Pre-Ann

Using our newly developed short pre-annealing and intermediate rolling process, the property of MgB₂/Fe tapes doped with nano-Si₃N₄ particles was further improved. The highest J_c value at 10 T and 4.2 K reached 6310 A/cm² in the sample doped with 1% nano-Si₃N₄ by using our new process, which was obviously higher than that of 4550 A/cm² obtained in the sample made via the conventional in situ PIT process. Furthermore, it was found that the improvement of J_c became smaller with increasing the doping concentration of nano-Si₃N₄ particles. This confirmed that our new process contributed to the J_c enhancement mainly through increasing the core density and connectivity. Adding more nano-Si₃N₄ introduced more impurities at the grain boundaries, which made our new process less effective.