This is at odds with usual theories of phonon-mediated superconductivity which assume that all electrons behave in the same manner.

As a consequence there is a conjectured new phase called the semi-Meissner state, in which vortices are separated by the critical distance.

[5] The simplest synthesis involves high temperature reaction between boron and magnesium powders.

[6] In the in situ variant, a mixture of boron and magnesium is reduced in diameter by conventional wire drawing.

The process of Reactive Mg Liquid Infiltration in a boron preform to obtain MgB2 has been a subject of patent applications by the Italian company Edison S.p.A.[citation needed] Hybrid physical–chemical vapor deposition (HPCVD) has been the most effective technique for depositing magnesium diboride (MgB2) thin films.

In contrast, the HPCVD system can grow high-quality in situ pure MgB2 films with smooth surfaces, which are required to make reproducible uniform Josephson junctions, the fundamental element of superconducting circuits.

[9] Various means of doping MgB2 with carbon (e.g. using 10% malic acid) can improve the upper critical field and the maximum current density[10][11] (also with polyvinyl acetate[12]).

[14]) The maximum critical current (Jc) in magnetic field is enhanced greatly (approx double at 4.2 K) by doping with ZrB2.

[15] Even small amounts of doping lead both bands into the type II regime and so no semi-Meissner state may be expected.

On the other hand, the quasiparticle states of small gap are loosely bound to the vortex core.

[16] Superconducting properties and low cost make magnesium diboride attractive for a variety of applications.

[18][19] For those applications, MgB2 powder is compressed with silver metal (or 316 stainless steel) into wire and sometimes tape via the Powder-in-tube process.

Decoy flares containing magnesium diboride/Teflon/Viton display 30–60% increased spectral efficiency, Eλ (J g−1sr−1), compared to classical Magnesium/Teflon/Viton(MTV) payloads.

[27] An application of magnesium diboride to hybrid rocket propulsion has also been investigated, mixing the compound in paraffin wax fuel grains to improve mechanical properties and combustion characteristics.