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Equations of state for B2 and bcc Fe1-xSix
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  • Yoshihiro Nagaya,
  • Hitoshi Gomi,
  • Kenji Ohta,
  • Kei Hirose
Yoshihiro Nagaya
Tokyo Institute of Technology

Corresponding Author:nagaya.y.ab@m.titech.ac.jp

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Hitoshi Gomi
Earth-Life Science Institute
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Kenji Ohta
Tokyo Institute of Technology
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Kei Hirose
Tokyo Institute of Technology
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Abstract

Composition, chemical disorder, and magnetism significantly affect the volume and bulk modulus of iron–silicon (Fe–Si) alloys at ambient pressure. Here, we computed the equations of state for bcc-like (ordered B2 and disordered bcc) Fe–Si alloys available up to the inner-core pressure using the first-principles Korringa–Kohn–Rostoker method. Ferromagnetic (FM) and nonmagnetic (NM) states over a wide composition range, from Fe to FeSi, were investigated. The results revealed that magnetism and chemical disorder increased the volume and decreased the bulk modulus even at high pressures. Comparing the results with the preliminary reference Earth model, we found that an unrealistically large temperature gradient is required if the inner core is composed of a bcc-like Fe–Si alloy.
09 Jan 2023Submitted to ESS Open Archive
17 Jan 2023Published in ESS Open Archive