1. Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, CZ 16200, Prague, Czech Republic
2. Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, Praha 8, Czech Republic
3. Max Planck Institute for Solid State Research, Heisenberg Strasse 1, 70569 Stuttgart, Germany
4. Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
5. Jülich-Aachen Research Alliance (JARA); Fundamentals of Future Information Technology, 52425 Jülich, Germany
6. Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 10, CZ 18228, Prague, Czech Republic