[6a-C18-1~12] 10.2 Fundamental and exploratory device technologies for spin

▲ [6a-C18-3] Geometrical effect on the spin accumulation signals in ferromagnet/insulator/Si tunnel junctions

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

Keywords:silicon, spin injection, three-terminal Hanle

The three-terminal Hanle (3TH) measurement has been frequently used to estimate the spin lifetime in semiconductors and the spin injection polarization in ferromagnet(FM)/insulator(I)/semiconductor(SC) tunnel junctions. However, little attention has been paid to the fact that 3TH signals are affected by the device structure when its electrode size or channel thickness are comparable to the spin diffusion length. Therefore, the device structure must be carefully considered to understand the spin physics more precisely. We have derived universal representation of the 3TH signals by integrating the impulse response over the junction area, and numerically calculated the conversion factors for spin lifetime and spin injection polarization. We experimentally verified our calculation results by investigating 3TH signals observed in FM/I/Si junctions having a Fe/Mg/SiO_xN_y/n⁺Si injector electrode with various shapes.