1. Department of Physics University of Kerala, Kariavattom, Thiruvananthapuram, Kerala 695581, India
2. Material Sciences and Technology Division, CSIR-National Institute of Interdisciplinary Science and Technology (CSIR-NIIST), Thiruvananthapuram, Kerala 695019, India
3. Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India