Effects of cold high pressure densification on Cu sheathed Ba 0.6K0.4Fe2As2 superconducting wire

Abstract

Cu sheathed polycrystalline Ba0.6K0.4Fe 2As2 superconducting wire was prepared by a two-step powder-in-tube method. A pressure of 2 GPa was applied to a short sample before heat treatment. Magnetization and transport measurements were performed to investigate the effects of cold high pressure densification on the microstructure and superconductivity. The cold pressed sample shows an improved self-field transport critical current density of 2.8 × 104 A/cm2 (Ic = 83 A) at 4.2 K, which is nearly as twice as the unpressed sample. However, both samples manifest pronounced weak-link behavior, suggesting the technique need to be further optimized. The comparison of properties between pressed and unpressed sample and related mechanism was discussed. © 2012 Published by Elsevier B.V.