Improved superconducting properties of in situ powder-in-tube processed Mg1.15B2/Fe wires with nano-size SiC addition
The field dependence of the superconducting properties and mechanism of nano-SiC doped Mg1.15B2/Fe wires was investigated systematically. Compared with the MgB2+10wt%SiC sample, the critical current, Jc under low magnetic field increase for Mg1.15B2+10wt%SiC sample due to the improved grain connectivity because of the excess Mg in the raw materials. The quality of connectivity is evaluated through the active area fraction, AF, based on the temperature dependence behavior of resistivity. The increased Jc under high magnetic field is attributed to the increased upper critical field, Hc2 and irreversibility field, Hirr for the electron scattering effects of the massive carbon substitution for boron, impurities, and defects.