• Corpus ID: 119075855

Experimental evidence of a body centered cubic iron at the Earth's core condition

  title={Experimental evidence of a body centered cubic iron at the Earth's core condition},
  author={Rostislav Hrubiak and Yue Meng and Guoyin Shen High Pressure Collaborative Access Team and G. Laboratory and Carnegie Institution of Washington},
  journal={arXiv: Geophysics},
The crystal structure of iron in the Earth's inner core remains debated. Most recent experiments suggest a hexagonal-close-packed (hcp) phase. In simulations, it has been generally agreed that the hcp-Fe is stable at inner core pressures and relatively low temperatures. At high temperatures, however, several studies suggest a body-centered-cubic (bcc) phase at the inner core condition. We have examined the crystal structure of iron at high pressures over 2 million atmospheres (>200GPa) and at… 

Figures from this paper

Ab initio melting temperatures of bcc and hcp iron under the Earth's inner core condition

There has been a long debate on the thermodynamic stability of iron phases under the Earth’s inner core conditions, mainly due to the considerable uncertainty in determining the melting temperatures

Electronic correlations in dense iron: from moderate pressure to Earth’s core conditions

  • L. Pourovskii
  • Physics
    Journal of physics. Condensed matter : an Institute of Physics journal
  • 2019
We discuss the role of dynamical many-electron effects in the physics of iron and iron-rich solid alloys under applied pressure on the basis of recent ab initio studies employing the dynamical

Ni Doping: A Viable Route to Make Body-Centered-Cubic Fe Stable at Earth’s Inner Core

With the goal of answering the highly debated question of whether the presence of Ni at the Earth’s inner core can make body-centered cubic (bcc) Fe stable, we performed a computational study based

Two-step nucleation of the Earth’s inner core

Using a persistent embryo method and molecular dynamics simulations, it is demonstrated that the metastable, body-centered, cubic phase of iron has a much higher nucleation rate than does the hcp phase under inner core conditions, which provides a key factor in solving the inner core nucleation paradox.

Electronic correlations and transport in iron at Earth’s core conditions

It is shown how the scattering due to interactions between electrons has a relatively weak impact on the electrical and thermal conductivities of iron at core conditions.

Low viscosity of the Earth’s inner core

It is shown by first-principles molecular dynamics that the body-centered cubic phase of iron, recently demonstrated to be thermodynamically stable under the inner core conditions, is considerably less elastic than the hexagonal phase.

Prediction of crystal structures and motifs in the Fe–Mg–O system at Earth’s core pressures

Fe, Mg, and O are among the most abundant elements in terrestrial planets. While the behavior of the Fe–O, Mg–O, and Fe–Mg binary systems under pressure have been investigated, there are still very

Pressure effects on the EXAFS Debye-Waller factor of iron.

Results show that the Debye frequency increases rapidly with compression, and beyond 150 GPa it behaves as a linear function of pressure, and the mean-square relative displacement curve drops robustly with pressure, which causes the enhancement of EXAFS signals at high pressure.

Iron and Its Compounds in the Earth’s Core: New Data and Ideas

Iron is the most abundant chemical element of the Earth’s core and makes up more than 85 wt % of its mass, with the remaining ~15% thought to be Ni and some lighter elements: Si, C, S, O, and H. The

Overview of HPCAT and capabilities for studying minerals and various other materials at high-pressure conditions

High-Pressure Collaborative Access Team (HPCAT) is a synchrotron-based facility located at the Advanced Photon Source (APS). With four online experimental stations and various offline capabilities,



The structure of Fe‐Ni alloy in Earth's inner core

The crystal structure of Fe‐10%Ni was investigated up to 340 GPa and 4700 K, corresponding to the Earth's inner core conditions by synchrotron X‐ray diffraction measurementsin‐situat ultrahigh

Stabilization of body-centred cubic iron under inner-core conditions

The Earth’s solid core is mostly composed of iron. However, despite being central to our understanding of core properties, the stable phase of iron under inner-core conditions remains uncertain. The

An ab initio molecular dynamics study of iron phases at high pressure and temperature

Direct simulation of iron crystallization demonstrates that liquid iron freezes in the bcc structure at the P of the IC and T = 6000 K, and the mechanism of bcc stabilization is explained, resolving most of the earlier confusion.

Melting of iron at the physical conditions of the Earth's core

New and re-analysed sound velocity measurements of shock-compressed iron at Earth-core conditions show that melting starts at 225±3 GPa and is complete at 260 ± 3‬GPa, both on the Hugoniot curve—the locus ofshock-compression states.

The Structure of Iron in Earth’s Inner Core

Packing the Core The packing and arrangement of atoms in Earth's solid inner core can dictate processes such as core growth and rotation. Seismology and modeling suggest the inner core is composed

Pure iron compressed and heated to extreme conditions.

Temperature-quenched experiments indicate that the fcc phase of iron can exist in the pressure-temperature region above 160 GPa and 3700 K, respectively, which means that the actual structure of the Earth's core may be a complex phase with a large number of stacking faults.

Temperatures in the Earth's core from melting-point measurements of iron at high static pressures

THE temperature distribution in the Earth's core places important constraints on the Earth's internal heat budget and on models of the geodynamo. The solid inner core crystallizes from a liquid outer