1. Münster University of Applied Sciences, Stegerwaldstrasse 39, 48565 Steinfurt, Germany
2. International Institute of Physics–UFRN, Campus Universitário Lagoa nova, 59078-970 Natal, Brazil
3. Department of Physics, Dr. B. R. Ambedkar National Institute of Technology, Jalandhar 144011, India
4. Centre for Advanced Study in Physics, Panjab University, Chandigarh 160014, India
5. Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom
6. Institute for Materials Science, TU Dresden, 01062 Dresden, Germany