1. Center for Innovative Integrated Electronic Systems, Tohoku University, 468-1 Aza-aoba, Aramaki, Aoba-ku, Sendai 980-0845, Japan
2. JST-ACCEL, 468-1 Aza-aoba, Aramaki, Aoba-ku, Sendai 980-0845, Japan
3. Center for Spintronics Integrated Systems, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
4. Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
5. WPI-Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
6. Graduate School of Engineering, Tohoku University, 6-6 Aza-aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan