X-ray Characterizations of Iron-based Superconductor Round Wires with Large Critical Current Density

Abstract

Characterizations of round wires of iron-based superconductors were performed by using two different X-ray techniques. The core of the round wire turns out to be concentrically textured. The texturing parameter (r) defined by r = I(002)/I(103) has a clear correlation with the value of the critical current density (J c) of the wire. Using ~18 m-long (Ba,A)Fe2As2 (A: K, Na) wires, small magnets was constructed and successfully generated a magnetic field as large as 3.1 kOe at I = 53 A. The wire for the magnet was carefully cut and local variation of the critical current (I c) was evaluated. Variation of the core area was also measured by using X-ray tomography for the segments with the largest and smallest I c. Obtained images demonstrates that the core has a certain degree of sausaging effect and it has good correlation with I c of the wire. Using the largest value of measured I c and the minimum core area of that segment, record-high value of J c = 71 kA/cm2 at 100 kOe has been achieved.