1. Condensed Matter Physics Department, National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, Romania
2. Physics Faculty, West University of Timisoara, Timisoara, Romania
3. Faculty of Electronics, Telecommunications and Information Technology, Politehnica University Timisoara, Timisoara, Romania
4. Institute for Advanced Environmental Research, West University of Timisoara (ICAM-WUT), Timisoara, Romania