1. Research center, Materials Research Centre, Coimbatore, India
2. Department of physics, Arulmigu Palani Andavar College of Arts and Culture, Palani, India
3. Department of physics, Arulmigu Palani Andavar Arts College for Women, Palani, India
4. Department of Physics, Bharathiar University, Coimbatore, India
5. Department of physics, Sri Meenakshi Govt. Arts College for Women, Madurai, India