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.