Measurements with Pressure

Several physical properties such as the electrical resistivity, AC susceptibility and AC heat capacity can be measured under applied hydrostatic pressure. To achieve this, a hydrostatic piston-cylinder pressure cell can be used. Pressure can be used to alter the properties of many systems, for example it can be used to tune many heavy fermion systems through a quantum critical point. While the volume of a system also be changed by chemical doping, this can introduce disorder and other unwanted changes, and therefore pressure allows for the system to be tuned in a more controlled, reversible manner. 

A diamond anvil cell (DAC) can achieve even higher pressures which is necessary for observing many novel phenomena. A DAC generates pressure from the two tiny diamond anvils, pressed into a metallic gasket. A standard ruby fluorescence technique is used to calibrate the pressure, to a precision of less than 0.01GPa.Either Daphane7373 or a methanol-ethanol mixture can be used as a pressure-transmitting medium.