Diamond as pressure sensor in high-pressure Raman spectroscopy using sapphire and other gem anvil cells

Abstract

We propose a new Raman pressure scale based on the shift with pressure of the fundamental Raman band of micrometer-sized diamonds. First, we confirmed that the pressure slope of the triply degenerate diamond phonon behaves in a similar fashion to that of the bulk. Our measurements were calibrated Raman against the Sm:YAG fluorescence pressure scale up to 5 GPa using a gasketed sapphire anvil cell. The most relevant features regarding the design of the anvil cell are briefly outlined. Measurements were performed under hydrostatic conditions using 4:1 methanol-ethanol as pressure-transmitting medium. The calibration pressures according to the relationship p(GPa) = 0.356[v(cm-1) - 1332.3] are considered to be accurate within about 0.1 GPa. The convenience of using micrometer-sized diamonds as pressure sensors in Raman studies using gem anvil devices is demonstrated with several examples. Copyright © 2003 John Wiley & Sons, Ltd.