Comparisons for the resistivity behaviors of different encapsulated MgB2 samples

Physical property characterization of bulk MgB2 superconductor

“…2). As far as the presence of minute amount of MgO is concerned, the same is seen in earlier reports as well [2,15,[25][26][27][28][32][33][34][35][36][37], but not always marked on the respective XRD pattern.…”

“…The lattice parameters are though close to our vacuum annealed MgB 2 [27], the presence of MgO is comparatively less in Argon annealed sample, as seen by XRD pattern (Fig.2). As far as the presence of minute amount of MgO is concerned, the same is seen in earlier reports as well [2,15,[25][26][27][28][32][33][34][35][36][37], but not always marked on the respective XRD pattern.…”

“…2. Except for a weak reflection at 2θ = 63 0 , corresponding to pure MgO [2,17,[25][26][27][28], the rest of the Bragg reflections are characteristic of the hexagonal MgB 2 structure. MgO peak is marked in the pattern in Fig.…”

“…The encapsulated raw MgB 2 pellet is than heated at desired heating temperatures (750 0 C) with a hold time (3 hours) and is finally quenched in liquid nitrogen (LN 2 ) [26,27]. However we realized that the vacuum annealing method results in highly porous samples [28], which in turn adversely affect the transport properties like electrical and thermal conduction, in particular. The effects of porosity, crystallization and alignment of grains on various physical properties of MgB 2 are previously discussed in a topical review by John M Rowell [29].…”

“…Magnetization measurements are carried out with a Quantum-Design 14 Tesla Physical Property measurement System (PPMS) having Vibrating Sample Magnetometer (VSM) attachment. , corresponding to pure MgO [2,17,[25][26][27][28], the rest of the Bragg reflections are characteristic of the hexagonal MgB 2 structure. MgO peak is marked in the pattern in Fig.…”