Space efficient opposed-anvil high-pressure cell and its application to optical and NMR measurements up to 9 GPa

TL;DR

This paper introduces a space-efficient opposed-anvil high-pressure cell capable of reaching 9 GPa, optimized for experiments like NMR that require large sample volumes, with reliable in situ pressure calibration methods.

Contribution

A novel high-pressure cell design using non-magnetic materials that improves space efficiency and supports NMR measurements up to 9 GPa.

Findings

Achieved pressure up to 9 GPa with a large sample volume.

Developed reliable in situ pressure calibration using ruby fluorescence.

Demonstrated the cell's suitability for NMR and NQR experiments.

Abstract

We have developed a new type of opposed-anvil high pressure cell with substantially improved space efficiency. The clamp cell and the gasket are made of non-magnetic Ni-Cr-Al alloy. Non-magnetic tungsten carbide (NMWC) is used for the anvils. The assembled cell with the dimension \phi 29mm \times 41mm is capable of generating pressure up to 9 GPa over a relatively large volume of 7 mm3. Our cell is particularly suitable for those experiments which require large sample space to achieve good signal-to-noise ratio, such as the nuclear magnetic resonance (NMR) experiment. Argon is used as the pressure transmitting medium to obtain good hydrostaticity. The pressure was calibrated in situ by measuring the fluorescence from ruby through a transparent moissanite (6H-SiC) window. We have measured the pressure and temperature dependences of the 63Cu nuclear-quadrupole-resonance (NQR) frequency of Cu2O, the in-plane Knight shift of metallic tin, and the Knight shift of platinum. These quantities can be used as reliable manometers to determine the pressure values in situ during the NMR/NQR experiments up to 9 GPa.