Elastic and magnetic properties of Fe3P up to core pressures: Phosphorus in the Earth's core
Elastic and magnetic properties of Fe3P up to core pressures: Phosphorus in the Earth's core
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DOI：
10.1016/j.epsl.2019.115974
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发表时间：
2020-02-01
影响因子：
5.3
通讯作者：
Chen, Bin
中科院分区：
文献类型：
--
作者：
Lai, Xiaojing;Zhu, Feng;Chen, Bin
Phosphorus (P) is considered a possible light element alloying with iron (Fe) in the Earth's core due to its siderophile nature and the ubiquity of P-bearing iron alloys in iron meteorites. The sequestration of P by liquid metals during the core formation possibly results in the relatively low concentration of P in the bulk silicate Earth. In this study, we performed single-crystal and powder X-ray diffraction, synchrotron Mossbauer spectroscopy and nuclear resonant inelastic X-ray scattering measurements in diamond anvil cells to investigate the elastic and magnetic properties of Fe3P under high pressures. Our X-ray diffraction results suggest that there is no structural phase transition up to 111 GPa. However, a volume collapse was observed at 21.5 GPa in Fe3P, ascribed to a magnetic transition as evidenced by synchrotron Mhssbauer spectroscopy results. Fitting the volume-pressure data by the Birch-Murnaghan equation of state gives bulk modulus K-T0 = 162.4(7) GPa, its first pressure derivative K'(T0) = 4.0 (fixed) and zeropressure volume V-0 = 370.38(6) angstrom(3) for the magnetic phase and K-T0 = 220(7) GPa, K'(T0) = 4.0 (fixed) and Vo = 357(1) angstrom(3) for the non-magnetic phase. Sound velocities of Fe3P were determined up to 152 GPa by nuclear resonant inelastic X-ray scattering, demonstrating that Fe3P bears a low shear velocity and high Poisson's ratio at core pressures compared to Fe and Fe3S. When forming a solid solution Fe-3(S,P) with Fe3S at core pressures, Fe3P may favorably influence the elastic properties of Fe-3(S,P) to match the seismic observations of the inner core. (C) 2019 Elsevier B.V. All rights reserved.
