Preparation of Ag-Sheathed Tl-Ca-Ba-Cu-O Superconducting Wire
In the Tl-Ca-Ba-Cu-O system, Tl-O single layered and double layered structures with general formulas Tl1Can-1Ba2CunO2n+3(n=1~6) and Tl2Can-1Ba2 CunO2n+4 (n=1 ~4) have been obtained. We fabricated Ag-sheathed Tl-Ca-Ba- Cu-O superconducting wires using powders of Pb-added Tl1Ca 3Ba2Cu4+O11 and of Tl2Ca2Ba2Cu3O10 phases whose critical temperatures are the highest among the respective structures. The production process of the wires was cold- working and heat treatment. The measurement of transport critical current was carried out in the range of magnetic fields from zero to 2.5T. The critical current density Jc at 77K for the wire of (Tl,Pb)1Ca 3Ba2Cu4O11 is 10800A/cm2, and that value for Tl2Ca2Ba2Cu3O10 wire is 5500A/cm2. There is a tendency for the wire specimens with homogeneous structure of superconducting phases to have high Jc values. The Jc of the (Tl,Pb)1Ca3 Ba2Cu4O11 wire decreases rapidly by 0.1T, while the decrease of Jc above 1T is not so remarkable. The magnetic field dependency of Jc of the Tl2Ca2Ba2Cu3O10 wire shows a two-step decrease in Jc versus B curves; the first step is from zero to 0.1T, and the second step is beyond 1T. The direction of the magnetic field against the plane of the wire does not considerably influence the Jc values of either of the wires, because the anisotropic property of the wire is small.
KeywordsCritical Temperature Critical Current Density Superconducting Phasis Magnetic Field Dependence Double Layered Structure
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- (2).T.Matsumoto, M.Okada, R.Nisiwaki, T.Kamo, K.Aihara, S.Matsuda, M.Seido, K.Ozawa, Y.Morii and S.Funahashi: Proc.ISTEC Workshop on Superconductivity, Oiso(1989),111.Google Scholar