[1] CSIR, Inst Minerals & Mat Technol, Adv Mat Technol Dept, Bhubaneswar 751013, Orissa, India
[2] Inter Univ Accelerator Ctr, New Delhi 110067, India
[3] Indian Inst Technol, Dept Phys, New Delhi 110016, India
[4] Inst Mat Sci Agh, Bhubaneswar 751013, Orissa, India
[5] Inst Phys, Bhubaneswar 751004, Orissa, India
[6] CSIR, Natl Ctr Nano Struct Mat, Mechatron & MicroMfg MSM Div, ZA-0001 Pretoria, South Africa