[Zurück]

M. Reissner, R. Daminov, M. Imayev, W. Steiner, M. Makarova, P.E. Kazin:
"Investigation of pinning in hot plastic deformed Bi2212/MgO composites";
in: "Proceedings of 6 th European Conference Applied Superconductivity (EUCAS) 2003", A. Andreone, G. Pepe, R. Christiano, G. Masullo (Hrg.); IOP Conf. Ser. 181, 2003, S. 2195 - 2201.

Fine-rained Bi2212 powder with admixture of small MgO-particles was sintered and subsequently hot plastic deformed at different T_d by simultaneous applying uniaxial pressure and torsion. The treatment led to high texture and a defect structure well suited for improved pinning, indicated by a strong increase of the critical current density J_c, the mean effective activation energy, and the irreversibility field. The change in pinning behaviour with T_d is explained by the interplay of three main pinning centres: intragrain dislocations, MgO particles, and low angle grain boundaries. The first two are dominat at low temperatures, whereas the latter is most important at higher temperatures.

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