Institut für Festkörperphysik



Measurements at very low temperatures

The experimental determination of ground state properties and their low-lying excitations is vital for many fields of condensed matter physics. In compounds with competing energy scales the temperatures below which no further phase transitions are expected may be exceedingly low, calling for measurements at very low temperatures.

Temperatures down to 12 mK can be reached in our top-loading 3He/4He dilution refrigerator in combination with external fields up to 17 T. Measurements are performed directly in the 3He/4He mixture; the available diameter for the experimental set-up is 22 mm.

The following measurement techniques are available:

  • Electrical Resistivity
  • Hall Effect
  • Magnetic AC Susceptibility
  • Resistivity and AC Specific Heat under Pressure

Other techniques are in development:

>> specific heat, DC magnetisation (cantilever), Thermopower, Nernst Effect

At present we focus on the investigation of intermetallic compounds with cage structure and/or unconventional properties such as quantum critical behaviour, Kondo insulating behaviour, unconventional superconductivity, co-existence of magnetism and superconductivity, or quantum tunnelling.

Top-loading dilution refrigerator

Fig.1: The currently reached base temperature is 12 mK. A magnetic field of 17 T is available. Various measurement techniques are realised with different inserts.
Contact: S. Bühler-Paschen, G. Hilscher, M. Müller, M. Reissner, W. Steiner, V. Martelli, J. Larrea, J. Hänel