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Dresden 2003 – scientific programme

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TT: Tiefe Temperaturen

TT 20: Postersitzung IV (Mesoskopische Systeme, Supraleitung: Massivmaterialien, Bandleiter, Pinning, Vortexdynamik, Transporteigenschaften, Korngrenzen)

TT 20.42: Poster

Thursday, March 27, 2003, 14:30–19:00, P2c, P2d

Imaging the electric field distribution of the high temperature superconductor YBaCuO by magneto-optics — •V. Born, K. Guth, E. Brinkmeier, Ch. Jooss und H. C. Freyhardt — Materialphysik, Universität Göttingen, Windausweg 2, 37073 Göttingen

We used EFIMO (Electric field imaging by magneto optics [1]) to study the spatial and temporal development of the electric field and dissipated power density of the high-temperature superconductor YBa2Cu3O7−x (YBaCuO). Resolutions better than 10 µm in space and 120 ms in time can be achieved. Compared to standard voltage-current measurements, EFIMO has six orders of magnitude higher sensitivity. Measurements of square shaped YBCO films on single crystalline substrates reveal, that even in homogenous films, the electric field E(x,y) exhibits a strong inhomogeneous, complex pattern. Whereas E(x,y) is approximately constant within a current domain, we observe local minima of E(x,y) which are related to the bending of currents at current domain walls. At low external magnetic fields, thermal relaxation gives rise to a variation of the size of Vortex and Meissner phases in the sample which are related to complex electric field patterns. Different mechanisms inducing the E(x,y) distributions in both phases are discussed. Finally, we present the local dissipated power distribution p(x,y) of different samples, and show that strong local maxima are present in the vicinity of artificial defects.
This work was supported by the Deutsch Forschungsgemeinschaft.

[1] Ch. Jooss, K. Guth, V. Born, J. Albrecht, Phys. Rev. B 65, 014505, (2002)

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