Comparing the superconducting performance of nC, B4C, and sucrose doped MgB2

The effect of nC, B4C, and sucrose doped MgB2 superconductors prepared under the same conditions in one patch were compared in this study. The samples were prepared in a stoichiometric ratio such that x = 1 in the composite (MgB2-xCx), and the sintering temperature was 750 degrees C. Considerable improvement in magnetic flux pinning was observed in nC and sucrose compared to the pure and B4C-doped MgB2 samples. Subsequently, similar behavior was found for the critical current density, J(C) (B, T), and upper critical magnetic field, B-C2 (T). The volume pinning force, F-P, of the nC-doped MgB2 sample reaches its maximum values (>2 GN/m(3)) at 20 K and 1.14 T. The corresponding J(C) is 1.87 x 10(5) A/cm(2), which is double the value of the pure sample. J(C) (9T,5 K) of nC-doped MgB2 was 50 times greater than the corresponding value of pure sample. The sucrose-doped MgB2 is the best in terms of B-C2 enhancement. The estimated B-C2 at 0 K of this sample shows a considerable value: B-C2 (0) similar to 33T.