Multifunctional Probe Station

With in-plane magnetic field, vertical magnetic field and multiple DC/HF probe configurations, this system integrates magneto-optical imaging with spin transport testing.

Key capabilities include:

  • Maximum vertical magnetic field: 1.8 T
  • Maximum in-plane magnetic field: 1.4 T
  • Variable temperature range: 4 K – 873 K
  • Suitable for imaging research of hard magnetic materials
  • Compatible with multiple DC and high-frequency probes
MOKE multifunctional probe station

Multifunctional Control System

Test Signal Control

The control system synchronises multiple signals for advanced magnetic experiments. Signals include:

  • Vertical magnetic field
  • In-plane magnetic field
  • Current signals
  • Microwave signals

All signals can be applied synchronously at microsecond (µs) level. Users can adjust:

  • Signal waveform
  • Amplitude
  • Frequency
  • Relative delay
MOKE control and signal synchronisation system

Image Processing

The system includes advanced image processing functions:

  • Real-time background subtraction
  • Automatic vibration drift correction
  • Noise reduction for high-precision imaging

Signal Analysis

  • Real-time display of magnetic field and current signals
  • Kerr image-based hysteresis loop scanning
  • Local analysis resolution up to 220 nm

Magnetic Domain Imaging

The system enables observation of magnetic domain structures in various materials including:

  • Perpendicularly anisotropic thin films
  • Nanofilm materials
  • Silicon steel surfaces
Magnetic domains in perpendicularly anisotropic thin films
Magnetic domains in nanofilm materials
Magnetic domains on silicon steel surface

Typical Applications

Magnetic Material Quality Detection

The system can evaluate magnetic material quality, for example in MgO(sub)/Co/Pt samples where lattice mismatch can cause film defects.

Mismatch-induced defects in MgO/Co/Pt film
Poor quality magnetic film with snowflake-like domains
High quality magnetic film with uniform domains

Defect Location Detection

Magnetic domain walls deform near defects producing a pinning effect. With high-resolution objectives, defect locations can be directly identified.

Magnetic domain wall deformation at defect locations

Spintronic Device Damage Detection

The system can detect magnetic instability caused by damage during microfabrication of spintronic devices.

Magnetic instability due to spintronic device edge damage

Hysteresis Loop Analysis

The Kerr imaging system enables detailed analysis of magnetic hysteresis behaviour.

Hysteresis loop analysis using Kerr imaging

Characterisation of Magnetic Parameters

Kerr microscopy enables characterisation of intrinsic magnetic parameters with local spatial resolution up to 220 nm.

  • Saturation magnetisation (M)
  • Magnetic anisotropy energy (K)
  • Exchange interaction constant (Aex)
  • Dzyaloshinskii–Moriya interaction (DMI)

Magnetic Domain Wall Dynamics Study

The system can measure dynamic motion of magnetic domain walls.

Domain Wall Velocity

v = d / t

Maximum measurable domain wall velocity: ~200 m/s

Spin Transport Testing + Imaging

The system supports electrical measurements combined with Kerr imaging. Supported experiments include:

  • Spin-transfer torque (STT) driven domain wall motion
  • Current-field coupled domain dynamics
  • Spin-orbit torque (SOT) switching analysis

With Keithley 6221 and 2182A instruments, the system can measure:

  • Hall effect
  • I-V characteristics
  • Magnetoresistance (MR)

Additional microwave equipment enables:

  • ST-FMR measurements
  • Second harmonic measurements

Imaging Performance

  • Resolution: 220 nm (100× oil immersion objective)
  • Resolution: 450 nm (long working distance objective)
  • Maximum field of view: 1.2 mm × 1 mm
MOKE imaging performance comparison