Instrumentation for high pressure Throughout the history of modern physics, major discoveries are often directly linked to instrumental advances. For example the discovery of superconductivity by Kammerlingh-Onnes was directly linked to his ability to liquify helium. Although today many physical measurements can be performed on commercial apparatus, it remains true that most “state of the art” measurements rely on instruments developed within laboratories.“Extreme conditions” of very low temperatures, very high magnetic field, and very high pressure, have brought many of the recent breakthroughs in solid state physics, allowing new states of matter as well as helping to understand material properties in their normal state. In IMAPEC particular emphasis has been put on developing new instrumentation for high pressure studies. High pressure is an extremely valuable tool in solid state physics. It allows one, by reducing the interatomic distances by as much as several percent to change the microscopic interactions within a solid. Monitoring these changes by the measurement of some macroscopic quantity , can greatly aid the understanding of the important interactions. Furthermore, by tuning these interactions to some pertinent value, in some cases the ground state can be radically modified, leading for example to the occurrence or disappearance of superconductivity or magnetic order.
Our developments are mainly based on the “diamond anvil cell”, a marvellous device for submitting a sample to hydrostatic pressures easily in excess of 10 GPa (105 atmospheres). We have adapted this technique in order to allow various kinds of measurements to be made including resistivity, specific heat, and susceptibility, with in addition the possibility of fine tuning the pressure at low temperature. All these measurements can be performed in extreme conditions of very low temperatures and high magnetic field.
Last update : 10/16 2009 (527)