[1] Govt Coll Univ, Ctr Adv Studies Phys, Lahore 5400, Pakistan
[2] Govt Coll Univ, Dept Phys, Lahore 54000, Pakistan
[3] Islamia Univ, Dept Phys, Bahawalpur, Pakistan
[4] Khawaja Fareed Govt Postgrad Coll, Dept Phys, Rahim Yar Khan, Pakistan
[5] Univ York, Dept Elect, Spintron Lab, York YO10 5DD, N Yorkshire, England
[6] Lahore Univ Management Sci, Dept Phys, Lahore, Pakistan
[7] King Saud Univ, Dept Phys & Astron, Coll Sci, Riyadh, Saudi Arabia