Enhanced critical current density in the low-temperature sintered Nb3Al superconductor with Sn doping

Additional Flux Pinning in Sn‐Doped Nb3Al Superconductor

“…The J c value of Nb 3 (Al 1− x Sn x ) superconductors prepared by mechanical alloying (MA) and subsequent low‐temperature sintering is an order of magnitude higher than that of Nb 3 Al. [ 7 ] Among the great many previous reports, our results shows excellent J c performance among doped Nb 3 Al superconductors.…”

“…For the purpose of obtaining better superconductivity, our group tried to dope Sn into the Nb 3 Al superconductor. [ 7 ] Sn doping can not only enhance the critical transition temperature ( T c ) of Nb 3 Al but also significantly boost Nb 3 Al's J c . The J c – H curves of Nb 3 Al before and after Sn doping are shown in Figure a.…”

“…Figure 1b shows the normalized pinning force F p / F p,max versus b ( H / H irr ) curves for Nb 3 (Al 1− x Sn x ) samples and its calculation method is described in detail in Li et al [ 7 ] According to the flux pinning models reported by Dew‐Hughes, [ 21 ] the value of b = H / H irr located at the maximum of the F p / F p,max curve can give us a prediction of the type of flux pinning mechanism. It shows that the b value of undoped Nb 3 Al is 0.25, which is approximately equal to the b value of the grain boundary pinning mechanism (0.2).…”

“…At present, the J c performance of Nb 3 Al has not yet reached the ideal value, for which researchers have made many attempts. [ 5–10 ] Doping has been proved to be one of the most effective ways to improve superconducting properties. [ 11–17 ] Doping of various metal elements, such as Ge, Ag, Ti, Si, and Ga, [ 11,12,16,18 ] into the Nb 3 Al superconductor has been tried.…”

Microstructure and Superconducting Properties of Rapid Heating, Quenching, and Transformation (RHQT) Powder‐in‐Tube Nb3Al Wires Doped with Sn Element

“…[ 13 ] Taking that Nb 3 Sn and Nb 3 Al are both of A15 structure into account, doping of Sn improved the J c properties of low‐temperature sintered Nb 3 Al. [ 14 ] For RHQT Sn‐doped Nb 3 Al wire prepared by clad chip extrusion (CCE), Sn addition not only enhanced the H c2 and high‐field J c property, but also determined the phase formation route of the A15 phase: [ 15 ] Depending on the Sn doping amount, the A15 phase is formed either from long‐range order of the disordered A15 phase or transformed through the bcc‐structure Nb(Al) ss phase. [ 10 ] Although the powder‐in‐tube (PIT) method can take advantage of the inherent flexibility on adding the third element easily with wide compositional choices available, there have been few reports on combining the PIT process with the RHQT technique.…”