Ferromagnetic bubble clusters in Y${}_{0.67}$Ca${}_{0.33}$MnO${}_3$ thin films

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.