Static compression experiments are crucial in understanding the behavior of materials at extreme pressures. A recent paper published in the Journal of Applied Physics by an international team of scientists from Lawrence Livermore National Laboratory (LLNL), Argonne National Laboratory, and Deutsches Elektronen-Synchrotron has introduced a new sample configuration that enhances the reliability of equation of state measurements in a pressure regime previously unattainable in the diamond anvil cell.
The LLNL team’s development of the toroidal diamond anvil cell has already pushed the static pressure limit in condensed-matter sciences, but further advancements in sample fabrication were necessary for conducting more complex experiments. The challenge of reaching pressures higher than 300 GPa in static compression experiments led to the innovation of a new sample package that not only solves the problem but also improves the compression environment, resulting in higher quality equation of state data.
The innovative sample package involves embedding the target material within a uniform capsule of soft metal, which acts as a pressure-transmitting medium. This 10-step microfabrication process ensures that stress is distributed uniformly around the sample material, crucial for achieving reliable equation-of-state measurements in the diamond anvil cell. The team utilized the LLNL-designed toroidal diamond anvil cell with a sample chamber approximately 6 µm in diameter, allowing for experiments at pressures exceeding 300 GPa.
The experiments were conducted at Argonne National Laboratory Sector 16 HPCAT and Deutsches Elektronen-Synchrotron PETRA-III. While the study focused on molybdenum with a copper pressure-transmitting medium, the versatility of this sample package design means it can be applied to a wide range of materials in various scientific disciplines. The development marks the beginning of sample-package microfabrication in the toroidal diamond anvil cell, with the potential to advance static equation of state calibrations across physics, chemistry, and planetary science materials into the multi-megabar range.
The successful implementation of this new sample configuration represents a significant milestone in static compression experiments, expanding the pressure range for reliable equation-of-state measurements. By enhancing the compression environment and improving the quality of data obtained, researchers are now able to calibrate the equation of state of materials at pressures more than two times higher than previously achieved in diamond anvil-cell-derived experiments. This breakthrough opens doors for further advancements in understanding material behavior under extreme pressure conditions, with broad implications for various scientific fields.
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