Affiliation: | 1. Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110, India;2. Department of Physics, Noorul Islam Centre for Higher Education, Kumaracoil 629 180, India;3. Physics Research Centre, S.T. Hindu College, Nagercoil 629 002, India;4. Department of Physics, Bishop Moore College, Mavelikara, Alappuzha 690 110, India;5. C.G.C. Section, National Physical Laboratory, New Delhi 110 012, India |