[1] Kyung Hee Univ, Dept Adv Mat Engn Informat & Elect, Integrated Educ Frontier Sci & Technol BK21 Four, Yongin 17104, South Korea
[2] Sungkyunkwan Univ, Dept Elect & Comp Engn, 2066 Seobu Ro, Suwon 16419, South Korea
[3] Korea Inst Sci & Technol, Ctr Spintron, Seoul 02792, South Korea
[4] Kyung Hee Univ, KHU KIST Dept Converging Sci & Technol, Seoul 02447, South Korea