[1] Doon Univ, Dept Phys, Dehra Dun 248001, Uttar Pradesh, India
[2] Univ Alberta, Dept Chem & Mat Engn, Edmonton, AB T6G 2V4, Canada
[3] Indian Inst Technol, Dept Phys, Kharagpur 721302, W Bengal, India
[4] Harish Chandra Res Inst, Allahabad 211019, Uttar Pradesh, India