Published online by Cambridge University Press: 18 March 2011
Using quantitative magneto-optics and an inversion scheme of Biot-Savart's law the local current carrying capability of various types of grain boundaries (GB's) and interfaces in YBaCuO thin films and bulk material was investigated. In all GB's and interfaces a spatial variation of the local critical current density jc was observed which, however, has different reasons, such as microstructural inhomogeneities, magnetic field dependence of jc and size effects in extended GB's and networks of low angle grain boundaries (LAGB's).