Regensburg 2004 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 31: Supraleitung: Vortexdynamik, Vortexphasen, Pinning

TT 31.5: Vortrag

Freitag, 12. März 2004, 11:15–11:30, H20

Magnetic flux pinning in bilayers of high-temperature superconductors and ferromagnets — •J. Albrecht, S. Soltan, and H.–U. Habermeier — Max–Planck–Institut für Festkörperforschung, Heisenbergstr. 1, 70569 Stuttgart

Epitaxial bilayers of YBCO and ferromagnetic perowskites such as doped lanthanum manganites or strontium ruthenate are grown on single crystalline substrates by pulsed laser deposition. From quantitative magnetooptical investigations we find that the critical current density in these bilayers strongly depend on the magnetization state of the ferromagnet [1]. This leads to a hysteretic behaviour of the critical currents in these structures which is absent if the ferromagnet is replaced by an oxidic metal. The observed effect can be explained by pinning of flux lines at the magnetic domain walls in the ferromagnet.

[1] J. Albrecht, S. Soltan and H.–U. Habermeier, Europhys. Lett. 63, 881 (2003).