Versatile device for low temperature in situ generation of forces up to 25 kN: Application to hydrostatic pressure experiments

We describe a versatile modular device built to generate forces up to 25 kN at cryogenic temperatures in order to achieve very fine in situ hydrostatic pressure tuning in the range 0–21 GPa. This device was designed to save time during measurements and protect the experimental setup by avoiding warming and cooling cycles to vary the pressure. The force is generated by a bellow operated with pressurized 4He and amplified mechanically. Diamond and sapphire anvil cells are used to perform electrical resistivity, magnetic susceptibility, and specific heat measurements under highly hydrostatic conditions by using helium as the transmitting medium. The pressure is determined by the ruby fluorescence technique. The performance of the device is illustrated by measurements of the superconducting transition of Pb and the magnetic transitions of CeRu2Ge2 in the range 0–10 GPa. This device is currently being adapted in a dilution fridge in order to be operated down to 50 mK.