Single-crystal elasticity of (Mg0.9Fe0.1)O to 81 GPa

Critical behavior of Mg1–xFexO at the pressure-induced iron spin-state crossover

“…We note that the ambient temperature BM or Vinet EOSs of MgO available in the literature or those employed here [32][33][34][35][36] are consistent with one another in the pressure range of interest [37] and that the choice of EOS does not change our results (see also Figure 2). In excellent agreement with previously published data [5][6][7]10,38], for pressures below the HS-LS crossover, the volumes of all Fp samples lie above the MgO compression line ("MGL" -MgO EOS line on Figure 1). Upon the further compression, the volumes of our single crystals drop significantly below the MGL after HS-LS crossover.…”

“…However, there are few single-crystal studies on Fp available and most of them either have no intrinsic information on pressure-density correlation [10,11] or have an insufficient number of points to provide conclusive evidence [12]. To the best of our knowledge, this study is the first on single crystal Fp covering a wide range of compositions at pressures close to the HS-LS crossover.…”

Spin crossover in ferropericlase and velocity heterogeneities in the lower mantle

“…It has been challenging for both experiments (15)(16)(17)(18)(19) and theory (20) to reach a consensus on this topic. Measurements often seemed to include extrinsic effects, making it difficult to confirm the spin crossover signature by different techniques and across laboratories.…”

“…Most of its properties are affected by the spin crossover. In particular, thermodynamics (14) and thermal elastic properties (15)(16)(17)(18)(19)(20) are modified in unusual ways that can change profoundly our understanding of the Earth's mantle. However, this is a broad and smooth crossover that takes place throughout most of the lower mantle and might not produce obvious signatures in radial velocity or density profiles (20, 21) (see Figs.…”

Thermodynamic estimation the compressibility of ferropericlase under high pressure

“…1 To date, the elastic properties of (Mg 1−x Fe x )O ferropericlase and its two end members (MgO and FeO) have been studied up to the core-mantle boundary conditions by means of in-situ synchrotron-based X-ray diffraction. [2][3][4][5][6][7][8][9] However, the large scattering of the measured bulk moduli of the MgO-FeO solid solution was observed to be most likely caused by the use of different pressure-medium conditions, 10 as well as the occurrence of phase transitions, a spin transition, and defect clustering as a function of the FeO component. [11][12][13] Therefore, the effect of the FeO content on the compressibility of (Mg 1−x Fe x )O remains ambiguous.…”