1. Department of Physics, Berhampur University, Berhampur-760007, Orissa, India
2. Department of Mathematics and Science, SMIT, Ankushpur, Berhampur, Orissa, India
3. Department of Physics, Temple City Institute of Technology and Engineering, Khurda, Orissa, India
4. Department of Physics, R. C. M. Science College, Khallikote, Ganjam, Orissa