Distribution of magnetic flux in high-Tcgrain-boundary junctions enclosing hexagonal and triangular areas

We report here scanning superconducting quantum interference device microscope measurements of the magnetic-flux-threading grain-boundary junctions that completely enclose hexagonal and triangular regions. While the total flux through one of these junctions is n${\mathrm{\Phi }}_0$, there are distinct areas of localized flux with magnitudes much less than ${\mathrm{\Phi }}_0$. We present the experimental results and discuss possible explanations for these observations.