• Title/Summary/Keyword: Tunnel junction

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Effect of barrier materials on the properties of magnetic tunnel junctions

  • 박병국;임우창;배지영;이택동
    • Proceedings of the Korean Magnestics Society Conference
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    • 2002.12a
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    • pp.66-67
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    • 2002
  • Magnetic tunnel junction에서는 spin의 tunneling이 가장 기본적인 현상이기 때문에 tunnel junction의 특성은 tunnel barrier의 성질에 크게 의존한다. Tunnel barrier로는 지금까지 $Al_2$O$_3$가 주로 사용되고 있다. 하지만 $Al_2$O$_3$의 경우는 barrier height가 2-3 eV로 높기 때문에 저 저항의 tunnel junction을 형성하기 위해서는 Al의 두께가 1nm 이하로 낮아져야 한다. 따라서 이를 극복하기 위해서 $Al_2$O$_3$ 보다 낮은 barrier height를 갖는 절연막을 tunnel barrier로 사용하고자 하는 연구가 많이 진행되고 있다 (예를 들면 TaOx [1], ZrOx [2], GaOx [3], and HfOx [4]). (중략)

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Macro-Modeling for Magnetic Tunnel Junction (Magnetic Tunnel Junction 의 Macro-Modeling)

  • 홍승균;송상헌;김수원
    • Proceedings of the IEEK Conference
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    • 2003.07b
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    • pp.943-946
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    • 2003
  • This paper proposes new SPICE Macro-Model of MTJ(Magnetic Tunnel Junction). This Macro-Model has five I/O terminals, reproduces MR characteristics including hysteresis and behaves correctly to time varying input signals. Furthermore, this Model can be easily modified to various MTJs with different characteristics by simply varying internal parameters.

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Magnetic tunnel junctions with thin free layer

  • 임우창;박병국;배지영;이택동
    • Proceedings of the Korean Magnestics Society Conference
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    • 2002.12a
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    • pp.68-69
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    • 2002
  • Magnetic tunnel junctions은 최근 자기저항용 재료나 MRAM용 소자로 사용하기 위한 연구가 활발하게 진행되고 있다. Magnetic tunnel junction을 저자계, 저전력용 소자로 사용되기 위해서는, 작은 switching field 값과 uniform한 switching field 분포를 가져야 한다. Micromagnetic simulation을 통하여 free layer의 두께와 포화 자화 값이 감소함에 따라서 switching field가 감소함을 알 수 있었다. 본 연구에서는 얇은 free layer를 사용하여 magnetic tunnel junction을 제조하고, 얇은 free layer가 자기저항에 미치는 영향에 대하여 알아보았다. (중략)

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Effect of temperature gradient on junction magnetoresistance of magnetic tunnel junction devices

  • No, Seong-Cheol;Park, Min-Gyu;Lee, Yeo-Reum
    • Proceeding of EDISON Challenge
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    • 2014.03a
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    • pp.495-497
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    • 2014
  • Combining the quantum transport theory with new field of Spin Caloritronics, we investigate on the influence of thermal gradient on the magneto tunnel junction structure under various circumstances. The results indicate enhancement in performance of spintronic device is possible using thermal energy.

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Macro-Model of Magnetic Tunnel Junction for STT-MRAM including Dynamic Behavior

  • Kim, Kyungmin;Yoo, Changsik
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.14 no.6
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    • pp.728-732
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    • 2014
  • Macro-model of magnetic tunnel junction (MTJ) for spin transfer torque magnetic random access memory (STT-MRAM) has been developed. The macro-model can describe the dynamic behavior such as the state change of MTJ as a function of the pulse width of driving current and voltage. The statistical behavior has been included in the model to represent the variation of the MTJ characteristic due to process variation. The macro-model has been developed in Verilog-A.

Low Temperature Properties of Exchange-biased Magnetic Tunnel Junction

  • Lee, K. I.;J. G. Ha;S. Y. Bae;K. H. Shin
    • Proceedings of the Korean Magnestics Society Conference
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    • 2000.09a
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    • pp.325-326
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    • 2000
  • Low temperature diagnosis was performed as a probe for the integrity of MTJ(Magnetic tunnel junction) process which is optimised for the given plasma oxidation condition. TMR ratio increased slowly with decreasing temperature than that expected from spin wave exitation theory〔1〕. Junction resistance (RJ) does not follow T$\^$-$\frac{1}{2}$/ law below 200 K, indicating another conduction path besides spin polarized tunneling is involved at low temperature. Temperature dependence of conductance dip and bias dependence of TMR with temperature are discussed, from which the quality of tunnel barrier and its formation process can be inferred.

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Tunneling Magnetoresistance in Si/$SiO_2$/NiFe/$Al_2$$O_3$/Co Thin Films (Si/$SiO_2$/NiFe/$Al_2$$O_3$/Co 박막의 투과자기저항 특성 연구)

  • 현준원;백주열
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.11
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    • pp.934-940
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    • 2001
  • Magnetic properties were investigated for Si/SiO$_2$/NiFe(300 )/A1$_2$O$_3$(t)/Co(200 ) junction related with the parameters of $Al_2$O$_3$. Insulating $Al_2$O$_3$ layer was formed by depositing a 5~40 thick Al layer, followed by a 90~120s RF plasma oxidation in an $O_2$ atmosphere. Magnetoresistance was not observed for tunnel junction with 5~10 thick Al layer, but magnetoresistance was observed large for tunnel junction with 15~40 thick Al layer. Oxidation time did not largely influence magnetoresistance. Tunnel magnetoresistance effect depended on magnetization behavior of two ferromagnetic layers. Tunneling junction was confirmed through nonlinear I-V curve. In this work, tunneling magnetoresistance(TMR) up to 30 % was observed. This apparent TMR is an artifact of the nonuniform current flow over the junction in the cross geometry of the electrodes.

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SPICE Macro-Model for Magnetic Tunnel Junction (Magnetic Tunnel Junction의 SPICE Macro-Model)

  • 홍승균;송상헌;김수원
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.40 no.2
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    • pp.98-103
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    • 2003
  • This paper proposes new SPICE Macro-Model of Magnetic Tunnel Junction (MTJ) This Macro-Model has five I/O terminals, reproduces MTJ MR characteristics including hysteresis and behaves correctly to time varying input signals. Furthermore, this Model can be easily modified to various MTJs with different characteristics by simply varying internal parameters.

EFFECT OF Zr-DOPED Al-OXIDE BARRIER ON THE TUNNEL MAGNETORESISTANCE BEHAVIOR

  • Choi, C.M.;Kim, Y.K.;Lee, S.R.
    • Proceedings of the Korean Magnestics Society Conference
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    • 2002.12a
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    • pp.60-61
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    • 2002
  • 현재 Magnetic Tunnel Junction는 고밀도 자기저항 헤드 및 비휘발성 메모리(MRAM)등의 자기저항 특성을 이용한 소자에 응용하기 위해 많은 연구가 진행되고 있다[1]. 하지만 Magnetic Tunnel Junction(MTJ)을 실제 소자로서 제작하여 사용하기 위해서는 smooth하고 pinhole이 없으며, 절연층 내부에 disorder나 defect가 없는 절연층을 형성해야 한다. (중략)

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