Comparisons for the resistivity behaviors of different encapsulated MgB2 samples

We report the comparisons of the effect on the resistivity behaviors for the four different encapsulated MgB2 samples where we optimized the pure MgB2, using the same standard solid-state synthesis technique, with different shielding materials. The encapsulations were done in Fe Tube, Ta Tube, Ta Foil and Mo Foil, respectively. For the overall comparison, Fe Tube encapsulation seems better sample than others. The lattice parameters 'a' and 'c' were found to be of the same order. The XRD patterns showed that the compound depicted the single-phase, which are crystallized in the hexagonal structure (space group P6/mmm) at room temperature, exhibited Tc of around 37-39 K. We could not completely avoid the inclusion of the foreign particles in our samples, despite having used several encapsulations, but the sample synthesized by this method holds the easiest way to attain better superconducting polycrystalline bulk MgB2.