1. Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
2. School of Nanoscience and Technology Kharagpur, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
3. School of Energy Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
4. Defence Materials and Stores R & D Establishment (DRDO), Kanpur 208013, India