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 measurement system

     

    Possible measurement

  • IV curve
  • MR with DC current source
  • MR with AC current source (including second harmonics)
  • Specification

  • Electromagnet : Maximum ~ 1T
  • Four single tip micromanipulators
  • Two SR830 lock-in amp
  • Keithley 6221 DC and AC sourcemeter
  • Keithley 2000 digital multimeter
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    Measurement example

  • SMR in W/CoFeB/MgO
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    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

    Measures THz range complex material parameters of sample, investigates THz Dynamics(spin wave) and other ps order effects.

     

    Specification

  • 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

  • GGG-Phonon Peak
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    MOKE Spectroscopic evaluator

     

    Specification

  • Light source spectrum : 300 ~ 2600 nm
  • Spectrometer range : 200~ 1100 nm
  • Max Field : ~1.36 kOe