• 제목/요약/키워드: spin injection

검색결과 95건 처리시간 0.022초

스핀 주입에 대한 퍼짐 이론 (Diffusion Theory of Spin Injection)

  • 이병찬
    • 한국자기학회지
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    • 제16권2호
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    • pp.121-129
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    • 2006
  • 자성체에서 비자성체로의 스핀주입(spin injection)을 설명하는 퍼짐이론(diffusion theory)에 대해서 살펴보았다. 먼저 기본 방정식을 유도하고, 그것을 강자성체/비자성체/강자성체 구조에 적용시켜, 스핀극나뉨과 자기저항을 구하였다. 주입된 스핀극나뉨 전류를 자기저항으로 검출하기 어려운 물리적 이유를 설명하고, 그 해결 방안에 대해서 논의하였다.

Spin Signals in Lateral Spin Valves with Double Nonmagnetic Bottom Electrodes

  • Lee, B.C.
    • Journal of Magnetics
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    • 제13권3호
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    • pp.81-84
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    • 2008
  • Spin injection and detection in lateral spin valves with double nonmagnetic bottom electrodes are investigated theoretically. Spin-polarized current injected from a magnetic electrode is split to two bottom electrodes, and nonlocal spin signals between the other magnetic electrode and the nonmagnetic electrodes are calculated from drift-diffusion equations. It is shown that the spin signal is approximately proportional to the associated current in the electrode.

Spin Transport in a Ferromagnet/Semiconductor/Ferromagnet Structure: a Spin Transistor

  • Lee, W.Y;Bland, J.A.C
    • Journal of Magnetics
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    • 제7권1호
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    • pp.4-8
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    • 2002
  • The magnetoresistance (MR) and the magnetization reversal of a lateral spin-injection device based on a spin-polarized field effect transistor (spin FET) have been investigated. The device consists of a two-dimensional electron gas (2DEG) system in an InAs single quantum well (SQW) and two ferromagnetic $(Ni_{80}Fe_{20})$ contacts: all injector (source) and a detector (drain). Spin-polarized electrons are injected from the first contact and, after propagating through the InAs SQW are collected by the second contact. By engineering the shape of the permalloy contacts, we were able to observe distinct switching fields $(H_c)$ from the injector and the collector by using scanning Kerr microscopy and MR measurements. Magneto-optic Kerr effect (MOKE) hysteresis loops demonstrate that there is a range of magnetic field (20~60 Oe), at room temperature, over which the magnetization in one contact is aligned antiparallel to that in the other. The MOKE results are consistent with the variation of the magnetoresistance in the spin-injection device.

Spin injection and transport properties of Co/Au/Y$Ba_2$$Cu_3$$O_y$ tunnel junctions

  • Lee, Kiejin;Kim, Sunmi;Ishibashi, Takauki;Cha, Deokjoon
    • Progress in Superconductivity
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    • 제3권1호
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    • pp.70-73
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    • 2001
  • We report the spin injection and transport properties of three terminal devices of Co/Au/$YBa_2$$Cu_3$$O_{y}$(F/N/S) tunnel junctions by injection of spin-polarized quaiparticles using a cobalt ferromagnetic injector. The observed current gain depends on the thickness of Au interlayer and is directly related to the nonequilibrium magnetization due to spin relaxation effects. The tunnel characteristic of a F/N/S tunnel junctions exhibited a zero bias conductance peak (ZBCP). The suppression of the ZBCP was observed due to the suppression of Andreev reflection at the interface, which is due to the spin scattering processes at the interface between a ferromagnetic and a d-wave superconductor.r.

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디젤 엔진의 분사각 변화가 배기가스에 미치는 영향에 관한 수치해석적 연구 (A Numerical Study on Effect of Variation of Injection Angle on the Emissions)

  • 배명직;이병화;한동식;전충환;장영준;송주헌
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회B
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    • pp.3085-3089
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    • 2008
  • In order to reduce NOx and Soot emissions simultaneously, characteristics of diesel spray and combustion were investigated by numerical simulation with StarCD in this paper. This work focuses on effect of Spin Injection. A simulation model of combustion, spray and emissions is developed for heavy duty marine diesel engine application. Simulation is performed with change of spray angle between first and second directions at fixed engine speed, injection timing, injection duration and etc. The results show that Spin Spray Injection method can reduce NOx emission. And the results show that the 1st injection considerably interfere with 2nd injection characteristics.

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Spin Valve Effect in Lateral Py/Au/Py Devices

  • Ku, Jang-Hae;Chang, Joon-Yeon;Koo, Hyun-Cheol;Eom, Jong-Hwa;Han, Suk-Hee;Kim, Gyu-Tae
    • Journal of Magnetics
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    • 제12권4호
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    • pp.152-155
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    • 2007
  • Spin dependent transport was investigated in lateral $Py(Ni_{81}Fe_{19})/Au/Py$ spin valve devices. Clear spin valve effect was observed in conventional four-terminal measurement geometry. Higher resistance was found in antiparallel magnetization field of two Py electrodes which is determined by anisotropy magnetoresistance (AMR) measurements. The rectangular shape of spin signal together with good agreement of switching field convinces observed spin valve signal is resulted from effective spin injection and detection. The magnetoresistance ratio decays exponentially with channel length by which spin diffusion length of Au channel was estimated to be 76 nm.