Space Efficient Opposed-Anvil High-Pressure Cell and Its Application to Optical and NMR Measurements up to 9 GPa

Abstract

We have developed a new type of opposed-anvil high pressure cell with\nsubstantially improved space efficiency. The clamp cell and the gasket are made\nof non-magnetic Ni-Cr-Al alloy. Non-magnetic tungsten carbide (NMWC) is used\nfor the anvils. The assembled cell with the dimension \\phi 29mm \\times 41mm is\ncapable of generating pressure up to 9 GPa over a relatively large volume of 7\nmm3. Our cell is particularly suitable for those experiments which require\nlarge sample space to achieve good signal-to-noise ratio, such as the nuclear\nmagnetic resonance (NMR) experiment. Argon is used as the pressure transmitting\nmedium to obtain good hydrostaticity. The pressure was calibrated in situ by\nmeasuring the fluorescence from ruby through a transparent moissanite (6H-SiC)\nwindow. We have measured the pressure and temperature dependences of the 63Cu\nnuclear-quadrupole-resonance (NQR) frequency of Cu2O, the in-plane Knight shift\nof metallic tin, and the Knight shift of platinum. These quantities can be used\nas reliable manometers to determine the pressure values in situ during the\nNMR/NQR experiments up to 9 GPa.\n