Physicochemical properties

The broader materials science approach leads to a wider range of physicochemical measurement techniques utilized.

Thermal transport – Light flash analysis is performed under inert atmosphere and allows to measure the thermal diffusivity between −100 °C and up to 500 °C. At lower temperatures, the thermal conductivity is monitored utilizing a thermal transport puck option (TTO) in a Physical Property Measurement System down to liquid helium temperatures.

Instrument specifications:

Temperature ranges −100 to 500 °C −271.35 to 125 °C
Heating rate 50 K/min ±0.5 K/min
Temperature diffusivity 0.01 mm2/s to 2000 mm2/s  
Accuracy ±3%  
Reproducibility ±2%  
Heat Capacity    
Accuracy ±5% < ±2% typical
Reproducibility ±3%  
Temperature conductivity 0.1 W/(m·K) to 4000 W/(m·K) 0.1 to 250 W/(m∙K)
Accuracy   min. ±5%
Resistivity   10 μΩ to 5 MΩ
Seebeck coefficient   1 μV/K to 1 V/K

Differential Scanning Calorimetry – Heat signatures and their enthalpy as well as heat capacities can be measured from liquid nitrogen up to about 700 °C in inert conditions. 

Instrument specifications:

Temperature range −180 to 700 °C
Cooling/heating rate 0.001 to 200 K/min (common ~10 K/min)
Measuring range ±750 mW (τ-sensor)

Seebeck Coefficient – The Seebeck coefficient (or thermopower) can be analyzed using a Seebeck analyzer with a linear 4-point probe. Temperatures between −125 and 500 °C allow a wide evaluation range to low temperatures.

Instrument specifications:

Temperature ranges −125 to 500 °C
Temperature accuracy 0.05°C
Sample geometries square, pellet, bar
Pellet sample dimensions Ø: 12.7 bis 25.4 mm
Seebeck-Coefficient range 10 to 2000 μV/K
Accuracy ±7%
Reproducibility ±3%
Electrical conductivity 0.05 to 150000 S/cm
Accuracy ±5%
Reproducibility ±3%

Hall Effect Measurement – A Van-der-Pauw 4-point probe with a permanent magnet setup allows to evaluate semi-conductors for their electronic properties down to charge carrier density and their Hall-mobility up to 600 °C.

Instrument specifications:

Temperature ranges  
Low to medium RT to 250 °C
High temperature RT to 600 °C
Temperature accuracy 0.05 °C
Magnetic field ±0.7 T
Resistance 10−4 up to 107 (Ωcm)
Charge carrier density 107 up to 1021 cm−3
Mobility 0.1 to 107 (cm2/Volt sek)

Speed of sound – Utilizing an ultrasonic pulse velocity probe the speed of sound in dense solid can be estimated.

Nanoindentation – The stiffness of materials can be measured using a nano-indenter – allowing (a more) effective bulk modulus determination.

Temperature Ambient
Atmosphere Inert (Ar)
Microscope 20x
Video FoV 648 x 486 µm
Displacement Range ±20 µm
Displacement Resolution 0.001 nm
Maximum load 50 mN (±3 nN)
Typical Resonant Frequency 150 Hz

Interested? – Feel free to request collaborative measurements or instrument access to marvin.kraft@uni-muenster.de or ptill@uni-muenster.de.