1. Department of Physics, School of Basic and Applied Sciences, Central University of Tamil Nadu, Thiruvarur 610 005, India
2. Department of Physics, Madanapalle Institute of Technology & Science, Madanapalle 517325, Andhra Pradesh, India
3. Centro de Fısica das Universidades do Minho e do Porto (CF-UM-UP), Campus de Gualtar, Braga 4710 057, Portugal