[1] Tohoku Univ, Elect Commun Res Inst, Lab Nanoelect & Spintron, Aoba Ku, 2-1-1 Katahira, Sendai, Miyagi 9808577, Japan
[2] Tohoku Univ, Ctr Spintron Integrated Syst, Aoba Ku, 2-1-1 Katahira, Sendai, Miyagi 9808577, Japan
[3] Tohoku Univ, WPI AIMR, Aoba Ku, 2-1-1 Katahira, Sendai, Miyagi 9808577, Japan
[4] Tohoku Univ, Ctr Innovat Integrated Elect Syst, Aoba Ku, 468-1 Aramaki Aza Aoba, Sendai, Miyagi 9800845, Japan