1. Institute of Experimental Physics SAS 1 , Watsonova 47, 04001 Košice, Slovakia
2. Faculty of Electrical Engineering and Informatics, Technical University of Košice 2 , Letná 9, 04200 Košice, Slovakia
3. Dr. K C Patel R&D Centre; Charotar University of Science and Technology, CHARUSAT Campus 3 , Changa, Gujarat 388 421, India