1. Department of PhysicsSt. Dominics College, Kanjirapally, Kottayam, Kerala 686512, India
2. Department of Polymer Research and Development, Central Power Research Institute, Sadasivanagar, Bangalore 560080, India
3. Department of PhysicsCMS College, Kottayam, Kerala, India
4. Solid State Physics LaboratoriesTimarpur, Delhi 110054, India
5. Universiti Teknologi MARA Faculty of Applied Sciences, 40450 Shah Alam, Selongor, Malaysia