Improvement of critical current density J (c) in powder-in-tube rapid heating, quenching and transformation Nb3Al wires by doping with nano-SnO2

摘要

We prepared Nb3Al superconducting wires doped with nano-size SnO2 (n-SiO2) particles through a multi-time rapid heating and quenching process and investigated their microstructure and superconducting properties. All the samples showed a highly homogeneous A15 Nb3Al phase. Compared with pure Nb3Al, the n-SnO2 doped Nb3Al wires presented a larger Delta T (c) value and a higher J (c) value. The best J (c) at 4.2 K was found in the 1 wt% n-SnO2 doped Nb3Al sample, with 3.37 x 10(5) A cm(-2), 2.55 x 10(5) A cm(-2) and 1.80 x 10(5) A cm(-2) at 8 T, 10 T and 12 T, respectively. These results were an improvement of about 60% compared with pure Nb3Al at the same applied fields. The maximum irreversible field value was obtained in the 1 wt% SnO2-doped Nb3Al wire, with a result of 29.5 T at 4.2 K. The improvement of J (c) performance in the n-SnO2 doped Nb3Al wires might be attributed to the formation of artificial nanoparticles in the grain, which act as extra effective flux pinning centers.