Using the high-resolution Faraday technique (HRF), we observed directly the nucleation of flux-lines of opposite sign in the remanent state of YBaCuO thin films. These negative flux-lines are nucleated by the stray fields caused by the pinned vortices. Due to the large demagnetizing factor of the thin film, this flux is able to penetrate the sample. Such a coupled behaviour can be observed directly. Experimental evidence for the existence of vortices of opposite sign is given. The influence of various polarizer/ analyzer settings on these observations is discussed. Furthermore, we show effects of flux-creep in thin films and the role of the negative flux-lines in this behavior is analyzed.
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