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TT: Tiefe Temperaturen

TT 1: Superconductivity - Fabrication, Technical Optimization and Characterization

TT 1.9: Vortrag

Freitag, 4. März 2005, 12:15–12:30, TU H104

Jc enhancement in YBa2Cu3O7−x thin films by metal doping — •J. Hänisch, C. Cai, R. Hühne, B. Holzapfel und L. Schultz — IFW Dresden, Helmholtzstraße 20, 01069 Dresden

Due to the sharp cube textures in RABiTS (rolling assisted biaxially textured substrates) tapes, grain boundaries are not the only Jc limiting factor anymore and flux pinning is now again a focus for further improvement of coated conductors in higher magnetic fields.
In this work, we present a comparative study of the influence of different metallic dopants (D: Ir, Ti, Zr and Hf) on Jc(B). Quasi-multilayer films of 40x(6.5 uc YBCO/n uc D) were prepared by pulsed laser deposition with a stoichiometric YBCO target and a metal target for the dopant, n being in the range of 0.04...0.3. In the case of Ir, nano-particles of BaIrO3 are growing epitaxially inside the YBCO film. Due to their larger lattice parameter of 4.1 Å compared to 3.9 Å (b-axis) in YBCO, the YBCO structure is under lateral stress. A certain degree of disorder on the Ba sites is expected because of the non-stoichiometry after precipitation. Both introduce extended and random defects respectively and lead to an enhancement in pinning force density and irreversibility field.
In addition, Zn doping is investigated as a possibility to enhance Jc in thin films. At doping levels of x < 0.05%, an increase in Jc in higher magnetic fields was found.

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DPG-Physik > DPG-Verhandlungen > 2005 > Berlin