Equation of state measurements have been improved significantly with the development of a new sample configuration by scientists from Lawrence Livermore National Laboratory, Argonne National Laboratory, and Deutsches Elektronen-Synchrotron. This advancement allows for reliable measurements in a pressure regime previously unattainable in the diamond anvil cell, pushing the boundaries of static pressure limit in condensed-matter sciences.
The toroidal diamond anvil cell designed by LLNL has been instrumental in achieving high-quality static equation-of-state measurements above 5 million atmospheres. However, the challenge lies in conducting static compression experiments to pressures higher than 300 GPa, as the compression environment is often suboptimal. The new sample package developed by the international team addresses this issue by providing an improved compression environment, which in turn enhances the quality of equation of state data.
Microfabrication Process
In a 10-step microfabrication process, the scientists embedded the target material in a uniform capsule of soft metal within the small sample chamber of the toroidal diamond anvil cell. This soft metal capsule acts as a pressure-transmitting medium, ensuring uniform stress distribution around the sample material even on a micron scale. The experiments were conducted at Argonne National Laboratory Sector 16 HPCAT and Deutsches Elektronen-Synchrotron PETRA-III, using molybdenum with a copper pressure-transmitting medium as a test case.
The development of this sample package marks a significant advancement in static equation of state calibrations. It opens up new possibilities for conducting static compression experiments in the multi-megabar range, where data is currently limited. According to LLNL scientist Claire Zurkowski, this method has the potential to revolutionize equation of state calibrations in physics, chemistry, and planetary science materials. The team anticipates that further advancements in sample-package microfabrication will push the boundaries even further in static compression experiments.
The collaboration between LLNL, Argonne National Laboratory, and Deutsches Elektronen-Synchrotron has resulted in a groundbreaking development in static equation of state measurements. By enhancing the sample configuration and microfabrication process, the team has paved the way for conducting experiments at pressures exceeding 300 GPa with unprecedented reliability and accuracy. This work represents a major stepping stone in the field of static compression experiments, with the potential to impact various scientific disciplines.
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