1. Institute of Advanced Ceramics, Hamburg University of Technology, Denickestraße 15, 21073 Hamburg, Germany
2. Institute of Optical and Electronic Materials, Hamburg University of Technology, Eißendorfer Straße 38, 21073 Hamburg, Germany
3. Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
4. ITMO University, 49 Kronverkskii Avenue, 197101 St. Petersburg, Russia
5. Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Straße 1, 21502 Geesthacht, Germany