1. Faculty of Science, Nepal Academy of Science and Technology, P. O. Box 3323, Khumaltar, Lalitpur, Nepal
2. International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, Tsukuba 305-0044, Japan
3. Department of Physics, Mizoram University, Aizawl 796-004, India
4. Department of Physics, Pachhunga University College, Aizawl 796-001, India
5. Department of Physics, Bose Institute, Kolkata 700-009, India