High-pressure experiments upgraded with extra diamonds

The capability to perform super-high-pressure experiments at up to 640 gigapascals (GPa) of static pressure will revolutionise experimental studies in the Earth and materials sciences. This equates to six million times the pressure of the air at Earth’s surface and  will allow for a more detailed in situ experimental investigation of the physical and chemical properties of solids; for example superconductivity, insulation and metallisation.

The experimental methods have been developed by an international team of scientists from the Universities of Bayreuth, Chicago and Antwerp, and investigated using high-resolution micro X-ray diffraction. High pressure experiments have been used since the 1950s to recreate the high pressure conditions of planetary interiors, e.g. the Earth’s core, as well as investigating the high pressure properties of materials. Previous experiments were able to reach static pressures of 420 GPa, and slightly higher with dynamic compression (shockwaves). Shockwaves take the samples to high pressures but also generate high temperatures, and can only produce nanoseconds of observation time, which has limited previous studies.

Diamond anvil cells work by subjecting a sample of micrometre size – smaller than the human eye can see – to a large force by compression between diamonds. The new higher pressures, which are 150 percent higher than typical experiments, have been created by adding a second set of micro-anvils that are made of newly engineered super-hard nanocrystalline diamond balls. These are less brittle than the typical single crystal diamonds and have a very high yield strength.

Further work aims to increase the pressure range even further upto 1000 GPa which would allow the study of the core conditions of planetary gas giants like Uranus and Neptune.

http://www.nature.com/ncomms/journal/v3/n10/full/ncomms2160.html#/discussion