Significant enhancement of critical current density in MgB₂ with HgO doping under high pressure

Abstract

A series of HgO-doped MgB 2 samples have been prepared under high pressure. Even 27 and 43 wt% impurities have been observed in the Mg 1.05Àx (HgO) x B 2 samples with x ¼ 0.05 and 0.075, the critical current density, J c , have been significantly improved under both low and high magnetic fields. XRD and scanning electron microscope (SEM) analyses revealed that HgO reacted with Mg to form MgHg alloy. The formation of MgHg alloy contributed not only to the refinement of MgB 2 grain size and improvement of grain connection, but also to homogeneous distribution of a large amount of impurities in the MgB 2 matrix. As a consequence, grain-boundary pinning was strengthened and new point pinning was generated. Effective improvement of flux pinning together with the very high impurity tolerance in HgO-doped MgB 2 samples might provide another potential route to prepare high-performance MgB 2 bulks and wires on an industrial scale.

Enabling High-Temperature Superconducting Technologies Toward Practical Applications

“…The Southwest Jiaotong University has reported the cooperative doping effects of Ti and nano-SiC on the enhancement of in-field J c performance of SiC doped MgB 2 tapes by a factor of 50-100% at 4.2 K and 10 T [83]. A series of HgO-doped MgB 2 samples have also been prepared and verified to achieve effective improvement of flux pinning together with very high impurity tolerance, which might provide another potential route to prepare high-performance MgB 2 bulks and wires on an industrial scale [84].…”