[1] St Xavier Coll, Mat Res Ctr, Dept Phys, Tirunelveli, India
[2] BS Abdur Rahman Univ, Dept Phys, Nano Res Ctr, Madras, Tamil Nadu, India
[3] iThemba LABS Natl Res Fdn NRF, UNESCO UNISA AFNET Nanosci, Mat Res Dept, Nanotechnol Labs, Cape Town, South Africa
[4] BS Abdur Rahman Univ, Dept Chem, Madras, Tamil Nadu, India
[5] BS Abdur Rahman Univ, Dept Mech Engn, Madras, Tamil Nadu, India
[6] Natl Isotope Ctr, GNS Sci, Lower Hutt, New Zealand