Seongcheol Noh

 nsc0316@gmail.com
 nsc0316@kaist.ac.kr



Education
  • 2016~present: KAIST, Ph.D candidate, EE
  • 2014~2016: KAIST, MS, EE
  • 2011~2014: KAIST, BS, Physics
  • 2008~2011: Korea Science Academy of KAIST


Research

        Topic: Quantum Transport in Spintronic Devices


       1. Analysis of magnetic tunnel junction (MTJ) structure using non-equilibrium Green's function (NEGF) method 



        2. Spin dynamics analysis in MTJ structure 
    
        NEGF-LLGS self-consistent calculation
  • Motivation
    • Electron spins had been ignored in conventional electronics, but today this field of research is exapanding considerably.
    • Spin-transfer torque (STT) is based on quantum mechanic effect, in which orientation of magnetic layer can be modified by angular momentum transfer.
    • Spin-transfer torque magnetic random access memory (STT-MRAM)  with MgO-MTJ is now considered as one of the promising candidates for future memory device.
  • Methodology
    • We exploit non-equilibrium Green's function (NEGF) method to describe quantum transport in such a nano-scaled electric device.
    • For the successive analysis of dynamic picture of MTJ, we solved Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation combining with NEGF.


       3. Two-dimensional micromagnetic simulator development


  • Example: "Step" cross-tie shape
    (Animated-gif => click the image)
(Rectangular shape)

(Arbitrary shape)
  • Spin torque calculation
  • Landau-Lifshitz-Gilbert (LLGS) equation

       4. Synthetic antiferromagnetic free layer-based device


       5. Strain effect study on MTJ stack
  • Stain effect on the magnetic anisotropy
  • Materials
    • Co_{x}Fe_{1-x} alloy
    • Heusler alloy
  • Simulation methodology
    • VASP - relaxation and MAE calculation
    • Siesta + Smeagol - DFT-NEGF calculation
    • in-house tools - transport calculation

Research Interests
  • Quantum Transport   
  • Spintronics


Publications
  • Journal
        1. Seongcheol Noh, Doo Hyung Kang, and Mincheol Shin, 
        "Simulation of Strain Assisted Switching in Synthetic Antiferromagnetic Free Layer-Based Magnetic Tunnel Junction",
        IEEE Transactions on Magnetics, vol. 55, no. 4, pp. 1-5, Apr. 2019.
  •  Selected Conference
        1. Seongcheol Noh and Mincheol Shin, "Quantum transport simulation of spin-transfer torque (STT):
            nonequilibrium Green's function approach", KCS, Incheon Korea Republic, 2015.

        2. Seongcheol Noh and Mincheol Shin, "Analysis of Magnetization Reversal in Magnetic Tunnel junctions with
            Self-consistent Calculation", AWAD, Jeju Korea Republic, 2015.

        3. Seongcheol Noh, Joon-Ho Lee, and Mincheol Shin, "Magnetic Tunnel Junction-Based Spin-Torque Oscillator                            Simulation: NEGF-LLGS Approach", ISPSA, Jeju Korea Republic, 2016.

        4. Seongcheol Noh, Doo Hyung Kang, and Mincheol Shin, "Theoretical study of strain-assisted synthetic 
            anti-ferromagnetic layer based magnetic tunnel junction switching", ISPSA, Jeju Korea Republic, 2018.

        5. Seongcheol Noh, Doo Hyung Kang, and Mincheol Shin, "Simulation of strain-assisted switching in antiferromagnetically             coupled synthetic free layer-based magnetic tunnel junction", NANOKOREA, KINTEX Korea Republic, 2019.