1. Kirchhoff Institute for Physics, University of Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
2. 4th Physics Institute and Research Center SCoPE, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
3. Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
4. Fraunhofer Institute for Ceramic Technologies and Systems, Materials Diagnostics, Maria-Reiche-Str. 2, 01109 Dresden, Germany
5. Centre for Advanced Materials, University of Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany