1. Centre for Materials Research, Department of Physics, Nehru Institute of Technology, Coimbatore, Tamil Nadu, India
2. Department of Physics, Condensed Matter Research Laboratory (CMRL), Bannari Amman Institute of Technology, Sathyamangalam, Tamil Nadu, India
3. Department of Science, Sona College of Technology, Salem, Tamil Nadu, India
4. Department of Physics (DDE), Annamalai University, Annamalai Nagar, India