1. J. E. S. Research Center, P. G. Department of Physics, J. E. S. College, Jalna 431 203, India
2. Centre for Materials for Electronics Technology, IDA Phase-II, Cherlapally, HCL (PO), Hyderabad 500 051, India
3. Department of Physics, Osmania University, Hyderabad 500 007, India
4. Department of Physics, Dr. B. A. M. University, Aurangabad 431 004, India