Adaptation of the Bridgman anvil cell to liquid pressure mediums

The advantage of Bridgman anvil pressure cells is their wide pressure range and the large number of wires which can be introduced into the pressure chamber. In these pressure cells soft solid pressure mediums like steatite are used. We have succeeded in adapting the Bridgman cell to liquid pressure mediums. With this breakthrough it is now possible to measure in very good hydrostatic pressure conditions up to 7 GPa, which is about twice the pressure attainable in piston-cylinder cells. The pressure gradient in the cell, estimated from the superconducting transition width of lead, is reduced by a factor of five in the liquid medium with respect to steatite. By the use of non-magnetic materials for the anvils and the clamp and due to the small dimensions of the latter, our device is specially suitable for magneto-transport measurements in dilution fridges. This pressure cell has been developed to measure very fragile and brittle samples like organic conductors. Resistivity measurements of (TMTTF)2BF4 performed in a solid and liquid pressure medium demonstrate the necessity of hydrostatic pressure conditions for the study of organic conductors at high pressures.