Affiliation: | a Materials Research Laboratory, Physics Department, Ewing Christian College, University of Allahabad, Allahabad 211003, India b Physics Department, University of Allahabad, Allahabad 211002, India c Institute of Chemistry, Military University of Technology, Warsaw 00-908, Poland d Centre of Materials Sciences, Institute of Inter Disciplinary Studies, University of Allahabad, Allahabad 211002, India |