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)