WB5-2

Effect of Mg addition on the critical current density of dense MgB2 bulk superconductors processed by spark plasma sintering
*Yiteng XING1, Pierre Bernstein1, Miryala Muralidhar2, Jacques Noudem1

In this study, we investigated the effect of Mg adding into bulk MgB2 superconductors on their superconducting properties. Highly dense bulk MgB2 samples were prepared by unconventional "Spark Plasma Sintering" (SPS). Different precursors were used: i) the commercial powder MgB2 and ii) mixtures of magnesium and nano boron powder (Mg + 2B) for an "in-situ" reactive synthesis. The amount of Mg added was 0.5, 1, 3 and 15wt% of 1.5g MgB2 powder. The density of the obtained MgB2 bulks was up to 99 % of the theoretical density of the material, which is the highest so far reported in literature. Then structural and microstructural characterizations were carried out with these samples and correlated to their superconducting properties, in particular their critical current densities (Jc) measured at 20 K. A high Jc = 675 kA/cm2 was obtained in self-field. Remarkably for a bulk MgB2, Jc was above 10kA/cm2 at 4T.

Keywords: MgB2