1. Institute of Physics of the Czech Academy of Sciences Na Slovance 2 Prague 8 18221 Czech Republic
2. Faculty of Mathematics and Physics Charles University Ke Karlovu 3 Prague 2 12116 Czech Republic
3. Laboratoire National des Champs Magnétiques Intenses Université Grenoble Alpes CNRS‐UPS‐INSA‐EMFL 25 rue des Martyrs, Boîte Postale 166 Grenoble Cedex 9 38042 France