This work was supported by the Swiss National Science Foundation (SNSF Professorship PP002-114711/1) and the University of Zurich. We thank Dr. B. Spingler, Institute of Inorganic Chemistry, University of Zurich, for helpful crystallographic discussions, and S. Weyeneth, Physics Institute, University of Zurich, for assistance with the magnetic measurements. We are grateful to Prof. A. Stemmer and R. Enning, Micro and Nano Science Platform, ETH Zurich, for help with AFM measurements. We thank Dr. R. Wepf, Electron Microscopy ETH Zurich, EMEZ, for Cryo-SEM investigations. The support of the Center for Microscopy and Image Analysis, University of Zurich, is gratefully acknowledged, and we thank Y. Zhou, UZH, for help with SEM measurements.