Static compression techniques and equations of state at extreme pressure

The double-stage diamond anvil cell (ds-DAC) and the toroidal-type diamond anvil cell (t-DAC) are new alternative techniques that break through the pressure generation limit of conventional DAC. Our group has developed the micro-paired and the conical support type ds-DAC, as well as t-DAC with various tip shapes, based on the sophisticated processing technology of the focused ion beam (FIB) system.

Here we report the volume-volume (V-V) (or density-density, ρ-ρ) interrelationships of seven metals (Fe, Cu, Mo, W, Re, Pt, Au) and two non-metal materials (MgO, NaCl) based on simultaneous static compression experiments at pressures exceeding 400 GPa using the t-DAC and the laser-heated DAC (LHDAC). The V-V data can be used to check the consistency of each primary scale proposed based on shock/ramp experiments, ultrasonic and/or Brillouin scattering measurements, and ab initio calculations, and allows us to construct internally consistent pressure scales.