Versatile device for low temperature in situ generation of forces up to 25kN: 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 hydrostati c pressure tuning in the range 0-21 GPa. This device was designed to save t ime during measurements and protect the experimental setup by avoiding warm ing and cooling cycles to vary the pressure. The force is generated by a be llow operated with pressurized He-4 and amplified mechanically. Diamond and sapphire anvil cells are used to perform electrical resistivity, magnetic susceptibility, and specific heat measurements under highly hydrostatic con ditions by using helium as the transmitting medium. The pressure is determi ned by the ruby fluorescence technique. The performance of the device is il lustrated by measurements of the superconducting transition of Pb and the m agnetic transitions of CeRu2Ge2 in the range 0-10 GPa. This device is curre ntly being adapted in a dilution fridge in order to be operated down to 50 mK. (C) 2000 American Institute of Physics. [S0034-6748(00)03306-2].