Review on high-performance bulk MgB₂ superconductors

Abstract

Although the fascinating effect of superconductivity was discovered more than one hundred years ago, only a few low-temperature superconductors, especially Nb3Sn and NbTi, have reached everyday-life use. After the discovery of superconductivity in MgB2 in 2001, a boom appeared in interest in employing MgB2 in commercial applications, facilitated by simple crystallographic structure, high critical temperature, low-cost raw ingredients, simple and fast production, and other advantages for moderate temperature applications. It only lacks high flux pinning and good mechanical performance. In this review, the implications of manufacturing procedures on the superconducting properties, crystal and electronic structure of MgB2 are discussed. The advantages and drawbacks of various manufacturing processes will be presented, as well as the ways how to improve MgB2 superconducting performance. The impact of oxygen reduction, elements doping, the introduction of defects and additives, and the effect of precursor refinement on superconducting properties are here compiled to give an overview of the progress of flux pinning enhancement in bulk MgB2.

A new perspective on ductile high-Tc superconductors under ambient pressure: few-hydrogen metal-bonded hydrides

“…Given that the superconductivity of MgB 2 has already undergone extensive theoretical and experimental examination, a detailed discussion is omitted here. For a more comprehensive understanding of its superconducting properties, please refer to [102,103].…”

Investigation of Layered Structure Formation in MgB2 Wires Produced by the Internal Mg Coating Process under Low and High Isostatic Pressures

“…Currently, MgB 2 wires made by the powder-in-tube (PIT) method are most often used in the construction and design of superconducting magnets for magnetic energy storage (SMES), wind turbines, magnetic resonance imaging (MRI), cables and electric motors [ 1 , 2 , 3 ]. This is due to the low anisotropy, inexpensive components, high critical temperature, high upper magnetic field, and low mass density of these materials [ 4 , 5 , 6 , 7 ]. These advantages are more important when the production of monocore or multi-filament PIT MgB 2 wires with lengths longer than 1 km is desired.…”

Comparison of the Field Trapping Ability of MgB2 and Hybrid Disc-Shaped Layouts

“…In addition, recent progresses in bulk fabrication techniques has allowed for the manufacturing of MgB 2 bulks with high trapped field values even in small-sized samples [ 20 , 21 ]. It was reported that the critical current densities and trapped field depend on the density and homogeneity of the MgB 2 superconducting material and pinning centers [ 19 , 22 ]. Studies indicated that the homogeneity and density of the superconducting MgB 2 material and the density of pinning centers can be improved by thermal treatment under high isostatic pressure or by an increase of the density of the MgB 2 material before the synthesis reaction [ 23 , 24 , 25 ].…”