1. Soft Materials Research Laboratory, Centre of Material Sciences, Institute of Interdisciplinary Studies, University of Allahabad, Allahabad 211002, India
2. Physics for Energy Division, National Physical Laboratory (Council of Scientific and Industrial Research), Dr. K. S. Krishnan harvesting Road, New Delhi 110012, India
3. Department of Physics, Banaras Hindu University, Varanasi 221005, India