[1] Bannari Amman Inst Technol, Dept Phys, Sathyamangalam 638402, India
[2] Natl Univ Singapore, Dept Phys, Singapore 117542, Singapore
[3] Natl Univ Singapore, Dept Mat Sci & Engn, Singapore 117546, Singapore
[4] Avinashilingam Univ Women, Dept Phys, Coimbatore 641043, Tamil Nadu, India
[5] Karunya Univ, Dept Phys, Coimbatore 641114, Tamil Nadu, India