RAPID COMMUNICATION: Significant improvement of critical current density in coated MgB2/Cu short tapes through nano-SiC doping and short-time in situ reaction
Pure and 10 wt% nano-SiC doped MgB2/Cu tapes were fabricated using the coating and pressing method. Samples were sintered by an in situ reaction process. It was observed that the nano-SiC doped tapes were significantly reacted with the Cu sheath at 700 °C, while pure samples have less reactivity with Cu under the same conditions. However, for sintering at 667 °C for just 6 min, the reaction with Cu was significantly reduced for the nano-SiC doped samples and led to very high critical current densities of more than 1 MA cm-2 in zero field at T \leqslant 10 K. The Jc values exceed 105 A cm-2 for 30 K in zero field, 20 K in 2 T and T \leqslant 10 K in 4 T. These Jc values are of one to two orders of magnitude higher than those of the pure MgB2/Cu short tapes, are the best reported Jc values for Cu sheathed wires and tapes and are comparable to the Jc values reported for MgB2/Fe tapes. These nano-SiC doped MgB2/Cu tapes also exhibited very small flux jumping at 5 K. Such a high Jc value and its field performance together with its possible high thermal stability make the Cu-sheathed MgB2 tapes an attractive candidate for large scale applications.