Ballistic spin transport in four-terminal NiFe/In0.75Ga0.25As structure

Yuuki Sato, Shin Ichiro Gozu, Tomohiro Kita, Syoji Yamada

Research output: Contribution to journalLetter

6 Citations (Scopus)

Abstract

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).

Original languageEnglish
JournalJapanese Journal of Applied Physics, Part 2: Letters
Volume40
Issue number10 B
Publication statusPublished - 2001 Oct 15
Externally publishedYes

Fingerprint

Two dimensional electron gas
Ballistics
ballistics
Electrodes
electrodes
Magnetoresistance
Field effect transistors
Hysteresis
Heterojunctions
diffusion length
mean free path
Modulation
electron gas
heterojunctions
field effect transistors
hysteresis
injection
Electric potential
modulation
probes

Keywords

  • Ballistic coupling
  • Four-terminal device
  • Mean free path
  • NiFe
  • Spin injection
  • Spin-diffusion length
  • Two-dimensional electron gas (2DEG)

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy (miscellaneous)
  • Physics and Astronomy(all)

Cite this

Ballistic spin transport in four-terminal NiFe/In0.75Ga0.25As structure. / Sato, Yuuki; Gozu, Shin Ichiro; Kita, Tomohiro; Yamada, Syoji.

In: Japanese Journal of Applied Physics, Part 2: Letters, Vol. 40, No. 10 B, 15.10.2001.

Research output: Contribution to journalLetter

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abstract = "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).",
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AU - Sato, Yuuki

AU - Gozu, Shin Ichiro

AU - Kita, Tomohiro

AU - Yamada, Syoji

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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).

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