1. Inorganic
Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, 45117 Essen, Germany
2. Ernst
Ruska-Center and Peter Grünberg Institute, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany