1. Division of Superconductivity and Magnetism Felix-Bloch Institute for Solid State Physics Universität Leipzig Leipzig 04103 Germany
2. Leibniz Institute of Surface Engineering (IOM) Leipzig 04318 Germany
3. Division of NMR Felix-Bloch Institute for Solid State Physics Universität Leipzig Leipzig 04103 Germany
4. Division of Applied Quantum Physics Felix-Bloch Institute for Solid State Physics Universität Leipzig Leipzig 04103 Germany
5. Technological Institute for Superhard and Novel Carbon Materials Troitsk Moscow 108840 Russia
6. Moscow Institute of Physics and Technology Dolgoprudny Moscow Region 141701 Russia