  We studied the ferromagnetic topology in a Y$_{0.67}$Ca$_{0.33}$MnO$_3$ thin
film with a combination of magnetic force microscopy and magnetization
measurements. Our results show that the spin-glass like behavior, reported
previously for this system, could be attributed to frustrated interfaces of the
ferromagnetic clusters embedded in a non-ferromagnetic matrix. We found
temperature dependent changes of the magnetic topology at low temperatures,
which suggests a non-static Mn$^{3+}$/Mn$^{4+}$ ratio.
