1. Department of Physics, Deenbandhu Chhotu Ram University of Science and Technology, Murthal, Haryana, India;
2. Department of Physics, Maharshi Dayanand University, Rohtak, Haryana, India;
3. Department of Physics, Chaudhary Ranbir Singh University, Jind, Haryana, India;
4. Department of Physics and Astro-Physics, University of Delhi, Delhi, India