Effects of Sintering Temperature on Superconductivity in undoped and SiC-doped MgB$_{2}$/Ti Wires

The effects of sintering temperature on the superconducting properties of both undoped and SiC-doped MgB$_{2}$ wires have been studied. The wires were fabricated by in situ powder-in-tube (PIT) method and characterized by x-ray diffraction, magnetization, scanning electron microscopy, and electrical resistivity measurements. Two groups of wire samples were prepared: the first group contains a pure MgB$_{2}$ core and the second contains MgB$_{2}$ core doped with 10 wt.{\%} of 20 nm SiC. Both groups of samples were sintered for 30 minutes at the following temperatures: 650 \r{ }C, 700 \r{ }C, 750 \r{ }C, 800\r{ }C, 850\r{ }C. It was found that the cores of these wires are almost in pure MgB$_{2}$ superconducting phase and the superconducting transition temperatures of the wires are about 36 K. For both groups of samples, the critical current density ($J_{c })$, measured at 5 K and 20 K in fields up to 7 Tesla, peaks up at sintering temperature 800\r{ }C. This result is in sharp contrast with recent results observed for Fe-sheathed wires for which the maximum $J_{c}$ was achieved at lower sintering temperatures. Detail discussion will be given to explain such dependence of $J_{c}$ on the sintering temperature.