Methods

Deposition of thin films


Sputtering system I and II (Leybold-Heraeus Z400)

  • Production of thin films via sputter deposition
  • Sputtering rates: about 0,25 up to 10 nm/min
  • Number of mounted targets: 3 (system I), 4 (system II)
  • Air lock allows faster change of samples without breaking the recipients vacuum
  • Alloys producible due to mosaic targets

Sputtering system III (Leybold-Heraeus Z700)

  • Production of thin films via sputter deposition
  • Sputtering rates: about 100 up to 200 nm/min
  • Number of mounted targets: 2 (1x DC, 1x HF)
  • Rotatable sample holder allows to process many samples at once
  • Reactive sputtering with oxygen or nitrogen possible

Sample characterization


GMR apparatus

  • four-probe-point measurement

Longitudinal MOKE

  • Magnetization measurement due to polarization rotation of the reflected He-Ne laserlight (magnetooptcal Kerr effect)
  • Differentiation measurement due to splitting the laserlight by a Wollaston prisma
  • Maximal (homogeneous) magnetic field: ???
  • Sensitive to the in-plane magnetization
  • Scan-Modus usable for automatic measurements

Surface profilometer (Dektak 3030)

  • Line-scan profiling of surface structures
  • Tip: 12.5µm radius (typ. diamond)
  • Measurement range in x-direction: 50µm to 50mm; in z-direction: 130µm to 5nm
  • Data points per µm: 0.04 to 40

Polar MOKE

  • Magnetization measurement due to polarization change from linear to elliptic of the reflected He-Ne laserlight (magnetooptcal Kerr effect)
  • Use of a Faraday modulator
  • Maximal (homogeneous) magnetic field: up to 2 T
  • Minimal step size of the magnetic field: 0.5 mT
  • Sensitive to the out-of-plane magnetization
  • Measurement at room temperature

Atomic and magnetic force microscope (Zeiss ULTRAObjective-System microscope)

  • Contact-modus for topographically flat samples (lateral resolution 0.5nm)
  • Non-contact-modus for soft/sensitive sample surfaces and samples with high topography (lateral resolution 1nm)
  • Field contrast modus: magnetic microscopy due to coated tips 
  • Range: 0.5µm x 0.5µm to 230µm x 230 µm
  • Max. z-piezo: 8µm

X-ray diffraction apparatus (Huber G 653)

  • Especially suitable for polycrystalline layer on amorphous or crystalline substrates
  • Guinier technique with Seemann-Bohlin geometry
  • Incident angle between imcoming x-rays and sample surface: 0.5° to 10°
  • Angle between imcoming and reflected x-rays: 30° to 140°
  • Measuring cell temperature: 35.0°C

Vibrating sample magnetometer

  • Proportional to the sample magnetization a current is induced at the pick-up coils due to the moving sample
  • Sensitive to in-plane or out-of-plane magnetization
  • Maximal applied magnetic field: ± 3T
  • Measurement temperature: 130 - 570K (due to heated flow of nitrogen)

Modification of magnetic properties


Ion bombardment apparatus I, II and III

  • Homogeneous sample bombardment with ions (typ. He+)
  • Well-defined modification of magnetic properties due to external magnetic fields (up to 100 mT)
  • Aperture: square between 1x1 and 12x12 mm²
  • Acceleration voltage: 5-30 kV
  • Working pressure: about 2·10-5 mbar
  • Ion current (2x2 mm² apperture): up to 2 µA

Field cooling apparatus

  • Initiating of the exchange bias effect
  • Working pressure: under 5·10-6 mbar
  • Maximal (homogeneous) magnetic field: 130 mT
  • Maximal temperature: 770 K