Abstract:
A comparative study on the structural and superconducting properties of MgB2 Powder-In-Tube (PIT)
wires doped with various weight percentage of nano carbon (n C), nano SiC (n SiC) and Burned Rice Husk
(BRH) has been carried out. X-Ray diffraction patterns of n SiC and BRH doped samples showed peaks of
Mg2Si which is a useful intragrain inclusion for flux pinning. The Lattice parameter ‘a’ decreased with
increasing doping concentration for all the doped samples, the maximum being for n C, indicating C
substitution for B. The Full Width at Half Maximum (FWHM) of (hk0) peaks of all samples increased with
doping. Doping caused a reduction in grain size and SEM images showed tightly packed smaller grains
containing hexagonal crystallites in all the three types of doped samples. All the dopants reduced the
transition temperature of the undoped sample and the effect was severe for n C doping. Unlike the pure
sample, the transport critical current density (JC) of the doped samples didn't fall rapidly at high fields;
but retained large fractions depending on the dopants. The best results were obtained for n SiC and BRH
doped samples with BRH closely matching the performance of n SiC. Improvement in critical current
density for these samples was an order higher than the undoped sample at 4.2 K and 8 T.
