1. Materials Science Group, Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India
2. Department of Physics, Badshahi Thaul Campus, HNB Garhwal University, Tehri Garhwal 249199, India
3. Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune 411008, India