1. Department of Condensed Matter and Material Sciences, S. N. Bose National Centre for Basic Sciences, JD Block, Sector 3, Salt Lake, Kolkata 700106, India
2. CSIR- Central Glass and Ceramic Research Institute, 196 Raja S. C. Mallick Road, Kolkata 700032, India
3. Department of Physics, Bose Institute, 93/1, Acharya Prafulla Chandra Road, Kolkata 700009, India