Pressure calibration of diamond anvil Raman gauge to 310GPa

Abstract

In order to develop an optical method for pressure determination in the multimegabar region, the first-order Raman spectra of diamond anvils were investigated at pressures up to 310GPa. The high-frequency edge of the Raman band, which corresponds to the Raman shift of the anvil culet due to the normal stress, was calibrated against the sample pressure derived from the equation of state of Pt. The obtained pressure dependence of the edge frequency demonstrates the reliability of this diamond anvil Raman gauge. Up to the maximum pressure of this study, the relation between Raman frequency and normal stress at the diamond anvil culet is formally similar to the equation of state of a hydrostatically compressed isotropic elastic body having a bulk modulus of K0=547(11)GPa and a pressure derivative of the bulk modulus K0′=3.75(20).

Raman shift of stressed diamond anvils: Pressure calibration and culet geometry dependence

“…This is likely the case for many of the other previous reports that do not observe a culet geometry dependence. [3][4][5] Furthermore, the precision of pressure measurements without a quasihydrostatic medium, which is the case for many of these studies, add to their data scatter. A comparison of our three culet designs versus that of other experiments is shown in figure 4.…”

“…[4] However, their choice of a relatively non-hydrostatic pressure medium makes it difficult to separate out other possible stress inducing effects on the diamond tip. This data fit is very similar to that from a study done by Popov, [3] which matches our 50 micron tip results up to 120 GPa and then nearly converges with Akahama et al [5] at much higher pressure.…”

“…In recent years it has been demonstrated that the Raman shift of the diamond tip at the sample-culet interface can serve as an in-situ pressure sensor at very high pressures [1][2][3][4][5] and be a useful alternative to the ruby luminescence standard. [6][7] This newer technique has the benefit of always having in place a pressure sensor very near the sample.…”

“…Applying these techniques has resulted in several different calibrations using a variety of functional forms. [2][3][4][5] The earliest published report detailing the use of the diamond anvil for pressure measurements went up to 30 GPa. [10] However, it has become increasingly common for diamond-anvil-cell experiments to exceed a megabar.…”

Hidden one-dimensional spin modulation in a three-dimensional metal

“…Hydrostatic pressure P provides continuous fine-tuning capability as well as a vast range with P4300 GPa accessible in diamond anvil cells 13 . However, tracking magnetism under pressure is technically difficult and often limited to indirect or spectroscopic techniques, such as electrical transport 6,14 , magnetostriction, X-ray emission 15 , nuclear magnetic resonance [2][3][4] and Mossbauer.…”