1. Institute for Physics, Martin-Luther-University Halle-Wittenberg, 06099 Halle, Germany
2. School of Mechanical, Industrial, and Manufacturing Engineering, Oregon State University, Corvallis, OR 97331, USA
3. National Institute for Research and Development in Electrochemistry and Condensed Matter, Aurel Paunescu Podeanu Street, No. 144, 300569 Timisoara, Romania
4. Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany