1. Department of Physics, Sardar Patel University, Shahid Chowk, Vallabh Vidyanagar, Anand, Gujarat-388 120, India
2. Department of Physical Sciences, P. D. Patel Institute of Applied Science, Charusat Campus, Highway 139, Off. Nadiad-Petlad Road, Changa, Gujarat-388 421, India
3. Department of Physics, The M. S. University of Baroda, Pratapgunj, Vadodara, Gujarat-390 002, India
4. Sophisticated Instrumentation Centre for Applied Research and Testing (SICART), Mota Bazaar, Vallabh Vidyanagar, Anand, Gujarat-388 120, India