[16a-501-1~11] 10.2 Fundamental and exploratory device technologies for spin

▼ [16a-501-7] Analysis of 3-terminal and 4-terminal spin signals in Si-based vertical and lateral devices

〇Shoichi Sato¹, Ryosho Nakane^1,2, Takato Hada¹, Masaaki Tanaka^1,3 (1.Tokyo Univ., 2.IIEEE, 3.CSRN)

Keywords:Spin injection, Hanle effect, Silicon

Recently, we have studied 3-terminal (3T) Hanle signals using a bulk Si substrate with Al/Mg/Fe/ Mg/MgO/n⁺-Si junctions (vertical device) and demonstrated that suppressing a magnetically-dead layer between Fe and MgO leads to the reduction of the broader 3T Hanle signal (B-3TH), which is not related with spin injection, and enhancement of the narrower 3T Hanle signal (N-3TH), which indicates spin injection into Si. The striking point is that the simple 3T measurements with proper analyses allow us to accurately estimate the junction resistance, spin polarization P_i, and spin lifetime τ_S, since electrons vertically pass through the junction. On the other hand, studying spin-related phenomena with the four-terminal (4T) nonlocal method is also important, because both τ_S and spin diffusion length λ_S can be estimated from the 4T Hanle signal (4TH) that is the strong evidence of the spin current transport. Previous analytical studies pointed out that N-3TH measured in a lateral device with a thin channel is different from that measured in a vertical device, ending up inaccurate P_i and τ_S estimation; however, precise analytic function and experimental demonstration are missing. In this study, we introduce analytic functions, and analyze N-3TH and 4TH signals measured in 4T devices and N-3TH signals obtained in our previous study, leading to the accurate estimation of P_i and τ_S.