Effect of heating rates on superconducting properties of pure MgB2, carbon nanotube- and nano-SiC-doped in situ MgB2/Fe wires -: art. no. 182504

The influence of heating rates and annealing temperatures on the transition temperatures (T-c) and critical current densities (J(c)) of pure MgB2, carbon nanotube- and nano-SiC-doped in situ monofilamentary MgB2/Fe wires was investigated. It was found that higher J(c) was obtained for pure MgB2 samples when heat treated with slower heating rates. SiC-doped samples also have higher J(c) with slower heating rates, but the J(c) is less sensitive to annealing temperatures. However, the J(c) of the carbon nanotube-doped wire was found to be insensitive to heating rates. The variation in T-c and J(c) with heating rate, and the different behaviors of differently doped MgB2/Fe wires, make it essential to carefully select the optimum heating rates for heat treatment. (C) 2005 American Institute of Physics.