1. Department of Electrical Engineering, Nagaoka University of Technology, Nagaoka 940-2188, Japan
2. Department of Electrical and Electronics Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui-shi, Fukui 910-8507, Japan
3. Toshiba Nanoanalysis Corporation, 8 Shinsugita-cho, Isogo-ku, Yokohama 235-8522, Japan
4. Institute of Physics, National Academy of Sciences of Azerbaijan, AZ 1143 Baku, Azerbaijan