1. Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, China
2. Electronic and Magnetic Materials Group (EMMG), PD, PINSTECH, PO Nilore, Islamabad, Pakistan
3. Department of Physics, Oslo University, Oslo, Norway
4. Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China
5. Nano-Scale Physics Laboratory, Department of Physics, Air University, PAF Complex, E-9, Islamabad, Pakistan