The Structure of Iron in Earth’s Inner Core

  title={The Structure of Iron in Earth’s Inner Core},
  author={Shigehiko Tateno and Kei Hirose and Yasuo Ohishi and Yoshiyuki Tatsumi},
  pages={359 - 361}
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 primarily of iron, but the structure is less clear due to anisotropic splitting of seismic waves. Tateno et al. (p. 359) performed static compression experiments on pure iron at the extremely high pressures and temperatures found in the inner core and saw that iron prefers a hexagonal close-packed… 

Oxygen-driven enhancement of electron correlation in hexagonal iron at Earth's inner core conditions

Earth’s inner core consists of mainly iron with a bit of light elements. Understanding of its structure and related physical properties has been elusive for both experiment and theory due to its

Crystal structure of iron at the center of the Earth

The inner core, most remote part of our planet, is composed of solid iron. Because the relevant ultrahigh pressure and temperature conditions were only accessible by dynamical shock-wave compression

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.

Viscosity of hcp iron at Earth’s inner core conditions from density functional theory

It is shown that dislocation creep is a key mechanism driving deformation of hcp iron at inner core conditions, and the associated viscosity agrees well with the estimates from geophysical observations supporting that the inner core is significantly less viscous than the Earth’s mantle.

Chemical Composition of the Outer Core

The Earth’s core is thought to composed of Fe⊖Ni alloys with large amounts of light elements. The composition of the present Earth’s outer core reflects various processes, such as core formation,

Toward a mineral physics reference model for the Moon’s core

The results indicate that the seismic velocities proposed for the Moon’s inner core by a recent reanalysis of Apollo seismic data are well below those of γ-Fe, which provides strong constraints to seismic models of the lunar core and cores of small telluric planets.

Superionic iron alloys and their seismic velocities in Earth's inner core.

Earth's inner core (IC) is less dense than pure iron, indicating the existence of light elements within it1. Silicon, sulfur, carbon, oxygen and hydrogen have been suggested to be the candidates2,3,

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

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

Light elements in the Earth’s core

Constraining the core’s composition is essential for understanding Earth accretion, core formation and the sustainment of Earth’s magnetic field. Earth’s outer and inner core exhibit a density

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



Elasticity of iron at the temperature of the Earth's inner core

First-principles calculations of the structure and elasticity of dense hexagonal close-packed iron at high temperatures find that the axial ratio c/a of h.c.p. iron increases substantially with increasing temperature, and a simple model of polycrystalline texture in the inner core is combined to account for seismological observations of inner-core anisotropy.

Lopsided Growth of Earth's Inner Core

It is proposed that the growth of the solid core implies an eastward drift of the material, driven by crystallization in the Western Hemisphere and melting in the Eastern Hemisphere, which generates an asymmetric distribution of sizes of iron crystals, which grow during their translation.

High-Pressure Elasticity of Iron and Anisotropy of Earth's Inner Core

A forward model of the inner core based on the predicted elastic constants and the assumption that the innercore consists of a nearly perfectly aligned aggregate of hcp crystals shows good agreement with seismic travel time anomalies that have been attributed to inner core anisotropy.

Stability of the body-centred-cubic phase of iron in the Earth's inner core

The results of molecular dynamics simulations of iron based on embedded atom models fitted to the results of two implementations of density functional theory found that both point to the stability of the body-centred-cubic iron phase at high temperature and pressure.

Body-Centered Cubic Iron-Nickel Alloy in Earth's Core

The experimental and theoretical results suggest that iron alloys with geochemically reasonable compositions (that is, with substantial nickel, sulfur, or silicon content) adopt the bcc structure in Earth's inner core.

Temperature and composition of the Earth's core

The Earth's core is a ball of swirling hot metal at the centre of our planet, with a radius roughly one half of the Earth's radius. It is formed by two parts: a solid inner core, with a radius of

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

Hemispherical anisotropic patterns of the Earth’s inner core

It is shown that the data collected are in good agreement with the presence of two anisotropically specular east and west core hemispheres, compelling evidence for the existence of a body-centered-cubic Fe phase at the top of the Earth’s inner core.

Light elements in the core: Effects of impurities on the phase diagram of iron

The stable phase of iron (Fe) in the Earth's core has been the subject of extensive studies, yet still remains controversial. Hexagonal close‐packed structure (hcp) is the accepted stable form of