Oxygen-enrichment of YBa 2 Cu 3 O 7-δ using the fluidization technique

The oxygen-deficient phase of the high T c superconductor, YBa 2 Cu 3 O 7 , was oxygen-enriched using the fluidization technique to give good superconducting properties. The normal method of oxygen treatment at 900°C for 24 h and at 600°C for 24 h has been reduced to just one treatment at 600°C for 12 h by the fluidization technique to achieve almost the same strength of superconducting signal for the YBa 2 Cu 3 O 7 powder, which establishes the attractiveness of the latter route for the large-scale preparation of superconducting material. The particle sizes were in the range 0-90, 90-180 and 180-420 μm. The fluidized particles were crystalline with orthorhombic distortion. T c onset , estimated using the a.c. magnetic susceptibility method, was 91·3 K. The volume fraction of superconducting material in the product was 83·7-85·3%, one of the highest values reported so far for YBa 2 Cu 3 O 7 .