Elastic and magnetic properties of Fe3P up to core pressures: Phosphorus in the Earth's core
[1];
[2];
[5];
[2]
- Univ. of Hawaii at Manoa, Honolulu, HI (United States); China Univ. of Geosciences, Wuhan (China)
- Univ. of Hawaii at Manoa, Honolulu, HI (United States)
- Argonne National Lab. (ANL), Chicago, IL (United States). Advanced Photon Source (APS); Univ. of Alabama, Birmingham, AL (United States)
- Argonne National Lab. (ANL), Chicago, IL (United States). Advanced Photon Source (APS)
- Univ. of Hawaii at Manoa, Honolulu, HI (United States); Univ. of Chicago, IL (United States)
- Univ. of Chicago, IL (United States)
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. Here, 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) Å3 for the magnetic phase and $$K_{T0}$$ = 220(7) GPa, $$K'_{T0}$$ = 4.0 (fixed) and $$V_0$$ = 357(1) Å3 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 Fe3(S,P) with Fe3S at core pressures, Fe3P may favorably influence the elastic properties of Fe3(S,P) to match the seismic observations of the inner core.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division; Consortium for Materials Properties Research in Earth Sciences (COMPRES)
- Grant/Contract Number:
- AC02-06CH11357; FG02-94ER14466
- OSTI ID:
- 1615477
- Alternate ID(s):
- OSTI ID: 1703134
- Journal Information:
- Earth and Planetary Science Letters, Vol. 531; ISSN 0012-821X
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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