facilities

Current setups

 

 

 

Laser Scanning Magnetic Microscope (LSMM)

 

Instrument specification

  • Beam size - minimum 1μm
  • Minimum scanning step - 100nm
  • Laser wavelength - 660nm
  • Laser maximum power - 110mW
  • Maximum out-of-plane field - About 1kOe
  • Maximum in-plane field - About 1kOe
  • Sample heating using Ceramic heater
  • No rotator, Current injection and Voltage measurement is possible.

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    What do LSMM measure?

  • Scanning sample geometry
  • Static Polar MOKE(Magneto-optic Kerr Effect)
  • Static In-plane MOKE
  • Magnetic domain imaging
  • Simultaneous electrical measurement (Magnetoresistance and Hall voltage)

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    Measurement example

     

     

     

    Magnetoresistance & Ferromagnetic Resonance measurement system

     

    Possible measurement

  • Magnetoresistance
  • First and second harmonic measurement
  • Spin-Orbit torque induced magnetization swtiching
  • Spin-Torque Ferromagnetic Resonance (ST-FMR)
  • Spin Hall Nano Oscillator (Auto-Oscillation)

    • Specification

  • ~1T Magnetic field
  • ~100mA DC & AC current
  • ~10μV resolution Voltmeter
  • ~0.1˚ resolved rotation
  • ~100nV resolution Lock-in amplifier
  • 9kHz ~ 40GHz, -20 ~ +10dBm Signal generator
  • 9kHz ~ 26.5GHz, -120 ~ -20dBm Spectrum analyzer

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    Measurement example

     

     

     

    Wide-field Kerr microscope (a.k.a 미경이)

     

    About Kerr microscope

     People usually depict each pole of magnet as blue and red. However, In reality magnetism is hardly visible. One way to observe magnetism optically is using magneto-optical kerr effect(MOKE), which is change of polarization after refection on magnetic surface. This wide-field polarized microscope is capable of coloring magnetization direction of magnetic film, either perpendicular or planar with either bright or dark field mode, applying external magnetic field.
     Current spatial resolution is ~0.5um, working on improving it. (both systemically and optically)

     Currently working on...

  • Improving spatial resolution
  • Enhancing signal to noise proportion

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    Measurement example

  • Expansion of domain wall

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    Low temperature probe station

     

    Specification

  • DC voltage noise : ~3uV
  • Out of plane field ~ 4000 Oe
  • Temperature range : 100K ~ 400K
  • Vacuum level : 1 torr

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    Feature

  • Applying temperature gradient
  • RF probe

    • Measurement example

  • Anormalous hall effect varying temperature

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    THz TDS

     

    THz-TDS can

    Measure THz range complex material parameters of sample: refractive index and conductivity. Also it can investigate THz Dynamics(spin wave) and other ps order effects.

     

    Specification

  • 8 K ~ 350 K
  • In-plane vector magnet (max. 300 mT)
  • THz spectroscopy range: 0.2THz ~ 4THz
  • Time resolution 0.33ps
  • Max Frequency resolution 1.2GHz
  • THz pulse peak amplitude below 100V/cm(0.33 Oe)

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    Measurement example

  • THz spectroscopy

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  • GGG-Phonon Peak

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    Magnetic Force Microscope (MFM)

     

    Specification

  • Acoustic enclosure with active vibration isolation table
  • Scan size – maximum 50 μm
  • Sample size – maximum 50 mm
  • manual XY stage (travel range 13 mm)
  • In-plane magnetic field – up to 500 Oe
  • Temperature control – up to 180℃
  • Direct on-axis optical microscope

    • Measurement example