Evaluation of global and local critical current densities in 122-type iron-based superconducting tapes

Abstract

We demonstrate the fabrication of (Ba,K)Fe2As2 superconducting pressed tapes through a powder-in-tube method using uniaxial cold pressing technique, and evaluate global and local Jc by several physical measurements. We found an intriguing anisotropy in Jc determined by magnetic measurements, which is related to microcrack structures affecting the local Jc. The maximum Jc estimated from magnetization measurements has reached ∼1.9×105A/cm2 under self-field at 4.2K. Furthermore, microcrack structures are directly observed by magneto-optical imaging technique.