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This file is the dataset used in the article "A molecular-scale origin of shear thinning and brittle failure of silicate melt", Geophysical Research Letters.

This file is the dataset used in the article "Rheology of nanocrystal-bearing andesite magma and its roles in explosive volcanism",Communications Earth & Environment.

惑星のコアの組成の多様性は、初期の太陽系におけるコア/マントルの進化と化学への知見を与える。地球物理データからコア組成を推測するには、コア形成材料の弾性特性の正確な情報が最も重要となる。 本論文です、液体Fe-Ni-S（17および30 at％S）およびFe-Ni-Si（29および38 at％Si）の高圧での音速と密度を測定し、圧力と組成の影響を報告する。

Precise information about the composition of the Earth's core is critical to understand planetary evolution and for discussing current hot topics in geodynamic behavior, such as core-mantle boundary heat flow. However, samples from deep in the Earth's interior are not available, so our knowledge is based on comparison of laboratory measurements with seismological observations, informed by meteorite composition, and indications of the Earth's core temperature. One of the most interesting results of such work has been the suggestion that Earth's inner core must contain light elements because the density of the core, as determined from seismological measurements, is lower than the density of pure iron, its main constituent, as determined from laboratory measurements and/or theoretical work: the density deficit is now considered to be ~4%. However, this conclusion relies critically on having an accurate pressure scale to relate lab generated pressures to geological pressures. Establishing such a scale has been the subject of intensive research but still involves significant extrapolation and approximations, especially at higher pressures. Further, a pressure scale to the multi-megabar pressures is indispensable for discussing super-Earth planets. Here we establish the first primary pressure scale extending to the multi-megabar pressures of Earth's core by measuring acoustic phonon velocities using inelastic scattering from a rhenium sample in a diamond anvil cell. Our new pressure scale agrees with previous primary scales at lower pressures and also shock compression experiments, but is significantly different from previous secondary and theoretical scales at Earth's core pressures: previous scales have overestimated, by at least 20%, laboratory pressures at 230 gigapascals. Our new scale suggests the density deficit of the inner core is ~9%, doubling the light-element content of the core.

Earth’s inner core likely consists of Fe-Ni alloy(s) plus a minor fraction of light element(s) to match the density and sound wave velocities of seismological models such as the preliminary reference Earth model (PREM). Among possible alloying light elements (e.g., Si, O, H, S, C), silicon is a popular candidate based on its cosmochemical abundance and potential involvement in chemical reactions at the core-mantle boundary. Previous work has shown that the solubility of Si in hcp-(Fe,Ni) alloy increases the stability field of the bcc-phase at high pressure. Comparison of sound velocity and density data of Fe-Ni-Si alloys with geophysical observations and theoretical predictions provide important constraints on the structure and dynamics of Earth’s inner core. However, knowledge of the high-pressure and high-temperature behaviour and properties of Fe-Ni alloys that contain light elements is limited. We therefore investigated bcc-Fe0.78Ni0.07Si0.15 alloy to compare its sound velocity and density with ab initio calculations and PREM in order to clarify the role of Si as a light element in Earth’s inner core.Compressional velocities and densities of bcc-Fe0.78Ni0.07Si0.15 alloy have been measured using inelastic X-ray scattering (IXS) and powder X-ray diffraction at the SPring-8 synchrotron facility (BL35XU beamline). High pressure was generated using a BX90-type diamond anvil cell. The metal alloy sample was loaded together with Ne (pressure medium) in a Re sample chamber and was mechanically compressed to 75 GPa through steps of 10 GPa at room temperature. IXS data were acquired at each pressure point in the range of momentum transfer of 4.24 to 7.63 nm-1. To determine density, we collected X-ray diffraction patterns of the sample before acquisition of each IXS spectrum using a flat panel detector installed in the optical system. All IXS spectra were fitted using Lorentzian functions. The dispersion relationship between energy (E) and momentum transfer (Q) was obtained by fitting all data with the following equation:E (meV) = 4.192 x 10-4 vp (m/s) x Qmax (nm-1) x sin (π/2 x Q (nm-1)/ Qmax (nm-1),where vp is the sound velocity of the sample.Preliminary results for bcc-Fe0.78Ni0.07Si0.15 show that the energy of the longitudinal acoustic phonon increases with increasing pressure. Additionally, we found that vp follows Birch’s Law, i.e., there is a linear relationship between density and sound velocity. Based on the comparison of our results and those for hcp-Fe and Fe-Si alloys reported previously with PREM, we propose that bcc-Fe0.78Ni0.07Si0.15 alloy is a viable candidate as a component of Earth’s inner core.

a 2D images of diffraction patterns of the Fe–S–Si system at 42.3–44.1 GPa (Run FESSI20) corresponding to the X-ray profile given in Figure 1(a). A at 44(1) GPa and 1450(50) K, B at 44(4) GPa and 1650(50) K, C at 44(4) GPa and 1730(50) K, and D at 42.2(0.3) GPa and 300 K after quenching from 1730 K. NaCl was used as the pressure medium and thermal insulator. b 2D images of diffraction patterns of the Fe−S−Si system at 49.2-58.2 GPa (Run FESSI10) corresponding to the X-ray profile given in Figure 1(b). A at 58(5) GPa and 1650(50) K, B at 54(4) GPa and 1810(50) K, C at 54(4) GPa and 1840(50) K, and D at 49.2(0.6) GPa and 300 K after quenching from 1840 K. (DOCX 1725 kb)