1. Department of Physics, National Institute of Technology Warangal, Hanumakonda, India
2. Department of Physics, Government College (Autonomous), Rajahmundry, India
3. Department of Physics, Faculty of Science, The M.S. University of Baroda, Vadodara, India
4. Applied Physics Department, Faculty of Engineering & Technology, The M.S. University of Baroda, Vadodara, India