[14a-C41-1~6] 10.2 スピントルク・スピン流・回路・測定技術

▼ [14a-C41-1] Relationship between 3-terminal signals and a dead layer of Fe/Mg/MgO/Si structure

〇Shoichi Sato¹、Nakane Ryosho^1,2、Hada Takato¹、Tanaka Masaaki^3,1 (1.EEIS Tokyo Univ.、2.IIIEE Tokyo Univ.、3.CSRN Tokyo Univ.)

キーワード：spin injection, three terminal Hanle, dead layer

Recently, many spin-dependent transport investigations using ferromagnetic metal (FM)/oxide (Ox) /Si tunnel structures showed two types of three-terminal (3T) Hanle signals; narrower Hanle signal (N-3TH) and broader Hanle signal (B-3TH). The origin of N-3TH is the spin accumulation in the Si, whereas that of B-3TH is still under discussion. From our theory, a magnetically-dead layer formed at a FM/Ox interface causes B-3TH and also reduces N-3TH due to the degradation of spin injection efficiency into Si[Sato et al., APL 107 2015]. In this study, we experimentally demonstrate that the spin injection efficiency is enhanced when the formation of magnetically-dead layer is prevented by inserting a Mg layer at the Fe/MgO interface. We also investigate the effect of the Mg insertion by measuring the Mg layer thickness dependence of N-3TH, B-3TH, and the saturation magnetization of Fe.