1. Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10/112, CZ 16200 Praha 6, Czech Republic
2. Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, CZ 12116 Praha 2, Czech Republic
3. Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Inés de la Cruz 3, E28049 Madrid, Spain
4. Instituto de Física Fundamental, CSIC, Serrano 121, E28006 Madrid, Spain
5. Regional Centre of Advanced Technologies and Materials, CATRIN, Palacky University Olomouc, Šlechtitelů 27, CZ78371 Olomouc, Czech Republic