Full text loading...
(a) An I-V curve of the Si channel at 8 K, which was measured by using a four-terminal method. (b) An I-V curve of the current injection circuit at 8 K, which was measured by using a two-terminal method. (c)–(f) Typical sample structures and measurement geometries in (c) non-local 4-terminal, and (d) non-local 3-terminal. An external magnetic field was applied along the z- and y-axis for Hanle and non-local magnetoresistance measurements, respectively. Non-local magnetoresistance observed at (e) 8 K and (f) 294 K, where clear hysteresis was observed. The bias electric current was set to be +3.0 mA.
(a) Hanle-type spin precession signals in the NL-4T method at 8 K, where the bias electric currents were changed from −4.0 mA to +4.5 mA in 0.5 mA steps. The inset shows the Hanle-type spin precession signals under parallel (red) and anti-parallel (blue) magnetization configurations. The solid lines are theoretical fitting lines. (b)–(d) The bias current dependence of (b) the spin accumulation signals, (c) the spin polarization, (d) the spin diffusion length, and (e) the spin relaxation time. An asymmetric dependence on the bias current was observed in the spin voltages and spin polarization, while the spin diffusion length and spin relaxation time were almost constant.
(a) Spin accumulation voltages in the non-local 3-terminal measurements under +1.0 mA (black open circles) and −1.0 mA (red open circles). The solid red line is the theoretical fitting line. Note that no signal was detected at 1.0mA, even after repeating the measurements several times and averaging the data. (b) Hanle-type spin precession signals in the NL-3T scheme at 8 K, where the bias electric currents were changed from −0.5 mA to −4.0 mA. (c) Bias current dependence of the spin accumulation signals under negative current conditions. Since no signal was detected under the application of a positive current, only the dependence under negative current conditions is shown. (d)Spin relaxation time as a function of negative bias current. The signal monotonically decreased as the negative current increased. (e) Spin transport length scale as a function of the bias voltages. The data point under zero bias current was obtained by using the NL-4T method because no spin drift took place in the NL-4T. The red dashed line is the least-squares fitting line using Eq. (3).
Article metrics loading...