METHOD FOR MAKING YTTRIUM-BARIUM-COPPER-OXIDE HAVING HIGH OFFSET SUPERCONDUCTING TRANSITION TEMPERATURE

摘要

A method of producing polycrystalline Y3Ba5Cu8Oy (Y-358) whereby powders of yttrium (III) oxide, a barium (II) salt, and copper (II) oxide are pelletized, calcined at 850 to 950° C. for 8 to 16 hours, ball milled under controlled conditions, pelletized again and sintered in an oxygen atmosphere at 900 to 1000° C. for up to 72 hours. The polycrystalline Y3Ba5Cu8Oy thus produced is in the form of elongated crystals having an average length of 2 to 10 μm and an average width of 1 to 2 μm, and embedded with spherical nanoparticles of yttrium deficient Y3Ba5Cu8Oy having an average diameter of 5 to 20 nm. The spherical nanoparticles are present as agglomerates having flower-like morphology with an average particles size of 30 to 60 nm. The ball milled polycrystalline Y3Ba5Cu8Oy prepared under controlled conditions shows significant enhancement of superconducting and flux pinning properties.