Enhanced Flux Pinning and Microstructural Study of Single-Domain Gd-Ba-Cu-O Bulk Superconductors With the Addition of Fe-Containing Alloy Particles

Introducing secondary-phase inclusions, especially magnetic particles, into the superconducting matrix is regard as an effective way to enhance the performance of high-temperature superconductors. The effect of Fe-B alloy additives on the microstructure and superconducting properties of top-seeded melt growth processed Gd-Ba-Cu-O bulk superconductors has been investigated systematically. Gd-Ba-Cu-O bulks 17 mm in diameter were melt-textured for various amounts of Fe-B additives in the range of 0-1.4 mol%. With the observations of scanning and transmission electron microscopy, the Fe-B alloy additives were found to decompose into Fe-containing particles with submicrometer in diameter. The refinement and homogeneous distribution of Gd₂BaCuO₅ inclusions seems to be improved remarkably. It leads to enhance flux pinning, flux trapping capability, and critical current density of Gd-Ba-Cu-O bulks, correspondingly. This phenomenon might be related to the magnetic interactions between the Fe-containing particles and the surrounding components, which may be the origin of the improvement of Gd₂BaCuO₅ nucleation process.