1. Department of Physics, Engineering and Astronomy, Austin Peay State University, Clarksville, Tennessee 37044, United States
2. Faculty of Physics, Opole University of Technology, Opole 45-370, Poland
3. Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, North Carolina 27401, United States
4. Équipe Verres et Céramiques (V&C), ISCR CNRS UMR 6226, Université de Rennes 1, Rennes 35042, France