Transport Critical Current Densities and <formula formulatype="inline"><tex Notation="TeX">$n$</tex> </formula>-Values of Multifilamentary <formula formulatype="inline"><tex Notation="TeX">$\hbox{MgB}_{2}$</tex></formula> Wires at Various Temperatures and Magnetic Fields

Abstract

A series of high-performing continuous-tube-filling-forming-fabricated (CTFF) powder-in-tube-type (PIT) MgB2 strands have been prepared, with critical current densities, Jcs, higher than 1.30×105 A/cm2 and n-values above 30 at 4.2 K, 5 T. The transport Jcs and corresponding n-values of a selected sample C1 were reported at temperatures, T, of 4.2-30 K and magnetic fields, B, of 0-12 T. The Jc - B data were fitted by Eisterer's percolation model and the temperature dependences of the fitting parameters were analyzed. The n - Jc curves showed a power law relationship n∞Jcm, also previously observed in state-of-the-art monocore MgB2 wires. Further analysis revealed that, like monofilamentary wires, the n(B, T) of this multifilamentary strand can also be estimated for all B and T based on the results of transport voltage-current (V- I) measurements made at one arbitrarily chosen temperature.