1. Centre
of Low Temperature Physics, Institute of Experimental Physics, Slovak
Academy of Sciences and Faculty of Science, P. J. Safarik University, 04001 Kosice, Slovakia
2. School
of Electrical and Computer Engineering, University of California, Davis, California 95616, United States
3. Institute
of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden, Germany
4. School
of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
5. Research
Institute of Superconductor Electronics, Nanjing University, 210093 Nanjing, China
6. Nuclear
Physics Institute, Academy of Sciences of the Czech Republic, 25068 Husinec-Rez, Czech Republic