1. Department of Chemistry, National Institute of Technology Hamirpur, Hamirpur (H.P.) 177005, India
2. Department of Materials Science and Engineering, National Institute of Technology Hamirpur, Hamirpur (H.P.) 177005, India
3. Department of Physics, University of the Free State, Bloemfontein 9301, Republic of South Africa
4. Department of Physics, Centre for Materials Science and Nanotechnology, University of Oslo, Oslo N-0316, Norway