1. School of Ceramic Engineering, Suranaree University of Technology, Nakhon, Ratchasima 30000, Thailand
2. School of Physics (SOP), University of Hyderabad, Hyderabad 500046, India
3. Centre for Advanced Studies in Electronics Science and Technology (CASEST), SOP, University of Hyderabad, Hyderabad 500046, India
4. Department of Physics, School of Engineering, University of Petroleum and Energy Studies, Dehradun 248007, India