Improved critical current properties observed in MgB2 bulks synthesized by low-temperature solid-state reaction

MgB 2 bulks were synthesized by the solid-state reaction of Mg and B at 600 °C and their superconducting properties were compared with samples heated at 850 °C. The samples heated at 600 °C exhibited improved critical current properties up to high fields at 20 K. Poor crystallinity is found to contribute enhancement of H c2 , H irr and J c at high fields. On the other hand, the strongly grain connected network structure and smaller grain size are responsible for high J c at low fields. Improved J c up to 3.93 × 10 5 A cm −2 and a high μ 0 H irr of T, as for undoped MgB 2 bulks, guarantees that low-temperature sintering is a promising way to fabricate MgB 2 conductors with high critical current performance.