Increased efficiency of batch-processed melt-textured YBCO

Abstract

Results on an established batch process preparing melt-textured YBCO in high quality and quantity will be reported. We used a standard composition Y1.5Ba2Cu3O7−X+1 wt% CeO2 without further doping to fabricate single-domain YBCO monoliths in different sizes and shapes (cylindrical, quadratic) as well as rectangular multi-seeded YBCO monoliths. Up to 2–3 kg melt-textured YBCO blocks are grown reproducibly in one box furnace run. Top seeding by self-made SmBCO was improved and rationalized. Optimization of oxygen annealing treatment leads to macro-crack free YBCO monoliths. Each YBCO monolith was characterized by integral levitation force and field mapping. In a single-domain quadratic monolith with an edge length of 38 mm a maximum induction of 1.44 T at 77 K and a distance of 0.5 mm was frozen. The reproducibility of the batch process is guaranteed. Mean maximum induction from 1.1 to 1.2 T at 77 K per batch was reached. A trapped magnetic field of 2.5 T was achieved between two single-domain monoliths in a gap of 1.5 mm at 77 K.