1. Solid State Research Laboratory, Department of Physics, Burdwan University, Burdwan 713104, West Bengal, India
2. Department of Physics, Dhruba Chand Halder College, Dakshin Barasat, South 24 Parganas 743372, West Bengal, India
3. A. Chełkowski Institute of Physics, University of Silesia in Katowice, 75 Pułku Piechoty 1, 41-500 Chorzów, Poland