[SIT23-P05] Sound velocity of liquid Fe-P alloy at high pressure
Keywords:Planetary cores, Liquid Fe alloys, Sound velocity, High pressure
We performed IXS measurements at the Quantum NanoDynamics beamline (BL43LXU)  of the RIKEN SPring-8 Center. The sample of Fe75P25 together with single crystal Al2O3 thermal insulators was compressed by a diamond-anvil cell (DAC), and then melted using the laser-heating system installed at the beamline. The longitudinal acoustic phonon mode of the liquid was measured in a momentum transfer range of 3-6 nm-1. The P-wave velocity of liquid Fe75P25 was determined up to 96 GPa based on the phonon dispersion relation obtained at each pressure condition. Based on the P-wave velocity determined at high pressures, we constructed the equation of state for liquid Fe75P25. We found that the influence of phosphorous on the sound velocity of liquid Fe  is almost negligible under the present experimental pressure conditions, while the phosphorous reduces the bulk modulus and density of liquid Fe.
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