Carbon nanohorn (CNH) doping of MgB2 wire prepared by suspension spinning was studied to enhance flux pinning. The mixed powders of MgB2 and CNH with nominal composition of (MgB2)0.95C0.05 were suspended in a mixed poly(vinyl alcohol) solution. The as-drawn filaments were hot-pressed under 20MPa at 200C for 8h. The samples were enveloped by an Fe sheet with a pellet of mixed powder of Mg and B and vacuum-sealed in a fused quartz tube, and then sintered (885 to 900C, 2–3h). The superconductivity of the samples was studied by electrical resistivity and SQUID method. No serious deterioration of TC was observed for the doped sample. The CNH doping resulted in enhancement of the transport JC values at 4.2K in high fields ranging from 6 to 10T by sintering at 885C for 2h. The superconductivity at 4.2K was maintained by applying the field of 14T for the doped sample sintered at 900C for 3h.

Carbon Nanohorn Doping in MgB2 Wire Prepared by Suspension Spinning. E.Ban, R.Sakaguchi, Y.Matsuoka, T.Goto, K.Watanabe, G.Nishijima: Physica C, 2005, 426-431[2], 1249-53