TY - JOUR
T1 - Ballistic spin transport in four-terminal NiFe/In0.75Ga0.25As structure
AU - Sato, Yuuki
AU - Gozu, Shin Ichiro
AU - Kita, Tomohiro
AU - Yamada, Syoji
PY - 2001/10/15
Y1 - 2001/10/15
N2 - Spin-injection experiments in NiFe/two-dimensional electron gas (2DEG)/NiFe four-terminal devices are described. The 2DEG was confined at a modulation-doped In0.75Ga0.25As/In0.75Al0.25As heterojunction interface. NiFe source-drain electrodes were located ∼ 1 μm apart and two voltage probes were fabricated between them. The separation between the NiFe electrodes was thus almost less than both the mean free path (∼ 2 μm) and the spin-diffusion length (> 1 μm) of the 2DEG. In nonlocal four-terminal measurements, where a constant current (i) was sent through one NiFe to one ohmic electrode, the two-terminal magnetoresistance (R2t = V2t/i) exhibited a spin-valve-like effect, while R4t = V4t/i showed a resistance hysteresis. The amplitude of the latter amounted to almost 12% of the R4t (B = 0) at 1.5 K, the extent of which was one order of magnitude larger than those so far reported. These results suggest the importance of a quasi-ballistic as well as a spin-coherent coupling between the two NiFe electrodes, which may crucial in the future operation of spin field-effect transistors (FETs).
AB - Spin-injection experiments in NiFe/two-dimensional electron gas (2DEG)/NiFe four-terminal devices are described. The 2DEG was confined at a modulation-doped In0.75Ga0.25As/In0.75Al0.25As heterojunction interface. NiFe source-drain electrodes were located ∼ 1 μm apart and two voltage probes were fabricated between them. The separation between the NiFe electrodes was thus almost less than both the mean free path (∼ 2 μm) and the spin-diffusion length (> 1 μm) of the 2DEG. In nonlocal four-terminal measurements, where a constant current (i) was sent through one NiFe to one ohmic electrode, the two-terminal magnetoresistance (R2t = V2t/i) exhibited a spin-valve-like effect, while R4t = V4t/i showed a resistance hysteresis. The amplitude of the latter amounted to almost 12% of the R4t (B = 0) at 1.5 K, the extent of which was one order of magnitude larger than those so far reported. These results suggest the importance of a quasi-ballistic as well as a spin-coherent coupling between the two NiFe electrodes, which may crucial in the future operation of spin field-effect transistors (FETs).
KW - Ballistic coupling
KW - Four-terminal device
KW - Mean free path
KW - NiFe
KW - Spin injection
KW - Spin-diffusion length
KW - Two-dimensional electron gas (2DEG)
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U2 - 10.1143/jjap.40.l1093
DO - 10.1143/jjap.40.l1093
M3 - Letter
AN - SCOPUS:0035888709
VL - 40
SP - L1093-L1096
JO - Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes
JF - Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes
SN - 0021-4922
IS - 10 B
ER -