1. 1Department of Physics, University College of Science, Osmania University, Hyderabad-500007, Telangana, India.
2. 2Department of Physics, University PG College, Osmania University, Secunderabad, Hyderabad, Telangana, India.
3. 3Department of Physics, B.V Raju Institute of Technology, Narsapur, Medak Dist, 502313, India.