1. Department of Physics, National Institute of Technology, Durgapur-713209, West Bengal, India
2. Department of Physics and Nanotechnology, Faculty of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur-603203, Tamil Nadu, India
3. Department of Physics, Sidho-Kanho-Birsha University, Purulia-723104, West Bengal, India
4. School of Nano Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India