1. School of Electrical and Electronic Engineering, Yonsei University, Seodaemun-gu 03722, Seoul, South Korea
2. Metallic Materials Development Department, Isehara Technical Center, TANAKA Kikinzoku Kogyo K.K., Kanagawa 259-1146, Japan
3. Advanced Institute of Convergence Technology, Seoul National University, Suwon 16229, Republic of Korea