1. Department of PhysicsSt. Xavier's College Thumba 695586 India
2. Department of PhysicsNirmalagiri College Nirmalagiri 670701 India
3. Center for Advanced MaterialsQatar University Doha P. O. Box 2713 Qatar
4. Department of PhysicsVIT‐AP University Amaravati Guntur India
5. New Technologies Research CenterUniversity of West Bohemia Plzeň Czech Republic