Melt process of Sm–Ba–Cu–O bulk superconductors by thin film cold seeding

Abstract

Abstract We discuss Sm123 bulks melt-processed in air and their characteristic superconducting properties for improving superconducting properties and producing a larger bulk. Isothermal undercooling growth in air with oxygen annealing and Nd123/MgO thin film cold seeding technique were applied in SmBaCuOy/Ag system to seek the high-efficiency of process, homogeneity of composition, and feasibility of batch production. We investigated process conditions such as heat treatment temperatures, compositions, seeding methods, and atmosphere. Single-domain growth of superconducting phases of a square larger than 10 mm on a side and 5 mm in thickness was achieved using this technique. T c,onset and T c,zero are 94 and 90 K, and J c is 3 × 10 4 A/cm 2 at around 2 T at 77 K with a typical peak effect in the LRE system. In the case of Sm211 = 10 and 40 mol% addition, the maximum trapped magnetic field of the bulks is 1000 and 2100 G, respectively. The maximum magnetic field increases as Sm211 volume fractions increase. The result implies that melt-processed in air applying isothermal method and thin film seeding in Sm system is feasible for producing larger bulks in large scale applications.