MgB2 superconducting wires were produced by the Mg diffusion method. Scanningelectron microscopy (SEM), optical microscopy, dispersive x-ray analysis (EDS)and XRD diffraction were used to study the physical structure and content ofthe wires. Magnetic properties (Tcm, Hc1, Hc2, Jc by the Bean model) wereobtained with a SQUID magnetometer, and transport properties (Tcr, Hc2,resistivity and residual resistivity ratio) were measured using a standardfour-lead configuration. The V-I characteristics of the wires close to thecritical temperature showed a staircase response, which was attributed to thepresence of weak links, creating phase slip centers. The origin of those weaklinks is discussed in relation to their formation and structure.
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