Effect of grain size and doping level of SiC on the superconductivity and critical current density in MgB/sub 2/ superconductor

S. Soltanian, University of Wollongong
X. L. Wang, University of Wollongong
J. Horvat, University of Wollongong
M. J. Qin, University of Wollongong
H. K. Liu, University of Wollongong
P. R. Munroe, University of New South Wales
S. X. Dou, University of Wollongong

Article comments

This article was originally published as: Soltanian, S, Wang, X, Horvat, J et al, Effect of grain size and doping level of SiC on the superconductivity and critical current density in MgB/sub 2/ superconductor, IEEE Transactions on Applied Superconductivity, June 2003, 13(2)3, 3273-3276. Copyright IEEE 2003.

Abstract

SiC doped MgB/sub 2/ polycrystalline samples were fabricated by in-situ reaction using different grain sizes (20 nm, 100 nm, and 37 /spl mu/m) of SiC and different doping levels (0, 8, 10, 12, 15 wt%). Phases, microstructures, superconductivity, critical current density and flux pinning have been systematically investigated using XRD, SEM, TEM, and magnetic measurements. Results show that grain sizes of the starting precursors of SiC have a strong effect on the critical current density and its field dependence. The smaller the SiC grains are, the better the J/sub c/ field performance is. Significant enhancement of J/sub c/ and the irreversibility field H/sub irr/ were revealed for all the SiC doped MgB/sub 2/ with additions up to 15 wt%. A J/sub c/ as high as 20,000 A/cm/sup 2/ in 8 Tesla at 5 K was achieved for the sample doped with 10 wt% SiC with a grain size of 20 nm. Results indicate that the nano-inclusions and substitution inside MgB/sub 2/ are responsible for the enhancement of flux pinning.