1. Department of Physics, Punjabi University, Patiala, Punjab 147 002, India
2. Advanced Materials Research Lab, Department of Basic and Applied Sciences, Punjabi University, Patiala, Punjab 147 002, India
3. Department of Physics, Dr. B. R. Ambedkar National Institute of Technology, Jalandhar, Punjab 144 011, India
4. Advanced Materials and Devices Division, CSIR-National Physical Laboratory, New Delhi 110 012, India