1. Centre for Research in Nanoscience and Nanotechnology, University of Calcutta, Technology Campus, Block JD-2, Sector III, Salt Lake City, Kolkata 700 098, India
2. Department of Physics, Bejoy Narayan Mahavidyalaya, P.O. Itachuna, Hooghly 712 147, India
3. Department of Physical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur Campus, BCKV Campus Main Office, Nadia 741 252, India
4. Materials Characterization Division, CSIR-Central Glass and Ceramic Research Institute, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700 032, India
5. Department of Material Science, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700 032, India