A look at the magnetic periodic table reveals that many elements have extremely low transition temperatures. Quantum Design systems—including the MPMS3 SQUID magnetometer and the PPMS DynaCool measurement platform—can achieve sample temperatures as low as 1.8 K, enabling measurements very close to absolute zero. This temperature range is fully sufficient for many applications.
However, investigating the superconducting transitions of certain elements requires even lower temperatures. Aluminum, gallium, zinc, and cadmium, for example, have transition temperatures ranging from 0.52 K to 1.14 K and therefore cannot be fully characterized using the standard MPMS3 or DynaCool configuration.

This is where specialized low-temperature options come into play. A helium-3 refrigerator is available for the MPMS3, allowing sample temperatures to be reduced to 0.42 K. This makes it possible, for example, to precisely measure the superconducting transition of cadmium at approximately 0.52 K. The DC magnetic moment is typically measured in an applied magnetic field of just 1 gauss.
For even lower temperatures, the DynaCool system can be equipped with a dilution refrigerator (DR). It uses the phase separation of a helium-3/helium-4 mixture below 1 K to continuously remove heat from the system. This allows temperatures as low as approximately 50 mK to be reached. Combined with the AC susceptibility option, this capability opens up new possibilities for investigating superconducting and quantum phenomena.
One example is the measurement of the magnetic susceptibility of Ir₀.₈Ru₀.₂ over a temperature range of 50 to 150 mK under different applied magnetic fields.
For researchers looking to reach even deeper into the millikelvin regime, the Proteox 5 mK from Quantum Design Oxford provides a continuous dilution refrigerator system. It is among the most powerful commercially available platforms for magnetic measurements at ultra-low temperatures.

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