The effect of synthesis temperature on the superconducting properties of n-SiC added bulkMgB2 superconductor

Abstract

We study the effect of synthesis temperature on the phase formation in nano(n)-SiC added bulkMgB2 superconductor. In particular we study: lattice parameters, amountof carbon (C) substitution, microstructure, critical temperature (Tc), irreversibility field (Hirr), critical currentdensity (Jc), uppercritical field (Hc2) and fluxpinning. Samples of MgB2 + (n-SiC)x with x = 0.0, 0.05 and 0.10 were prepared at four different synthesis temperatures, i.e. 850, 800, 750 and700 °C with the same heating rate and holding time of10 °C min − 1 and 2.5 h, respectively.We found 750 °C to be the optimal synthesis temperature for n-SiC doping in bulkMgB2 in order to get the best superconducting performance in terms ofJc,Hc2 andHirr. Carbon substitutionenhances the Hc2 while the low temperature synthesis is responsible for the improvement inJc due to the smaller grain size, defects and nano-inclusion induced by incorporation of C into theMgB2 matrix, which is corroborated by HRTEM (high-resolution transmission electronmicroscopy) results.