Was measured for the first time the behavior of iron under conditions similar to the Earth's core

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The international study, in which researchers from CONICET participated, provides new information to understand the origin of the Earth’s magnetic field, the speed of seismic waves and the evolution of other rocky planets.

Experiments and simulations of iron under the pressure and temperature conditions of Earth’s core reveal unexpected results regarding iron’s hardness. Credit: Brian Chavez/LLNL and the University of Mendoza.

An international research team, including scientists from CONICET (Argentina’s National Scientific and Technical Research Council), has successfully measured, for the first time, the dynamic strength of iron (Fe) under pressure and temperature conditions comparable to those of Earth’s inner core. The study, recently published in the journal Nature Communications, provides new insights into the speed at which seismic waves are transmitted, explains the origin of Earth’s magnetic field, and helps us understand how other rocky planets or asteroids with similar cores evolve.

“Dynamic strength could be described, in simplified terms, as the “toughness” of a material. Strength depends on the rate at which a material deforms. In most studies, deformation is evaluated at very low rates, which is why we talk about static or quasi-static “toughness.” However, in this study, a very high rate of deformation was applied to measure the strength of iron; that is why we talk about dynamic strength,” explained Eduardo Bringa, a CONICET researcher in the Materials, Astrophysics and Physics Simulations Group (SIMAF) at the Faculty of Engineering of the University of Mendoza (UM), who was part of the team that carried out the study.

According to the scientist, the extreme conditions at Earth’s core include pressures of between three and four million atmospheres and temperatures of between 4,000 and 7,000 degrees Celsius. Until now, no experiments with iron under these conditions had been conducted. To reproduce them, the scientific team combined experiments carried out at the National Ignition Facility (NIF) of Lawrence Livermore National Laboratory in the United States with advanced computer simulations.

The experiments conducted at the NIF enabled ultrafast X-ray and optical diagnostics to monitor the material’s evolution as it deformed. Subsequently, the experimental data were interpreted using hydrodynamic (microscopic scale) and molecular dynamics (atomic scale) simulations, providing a more complete picture of iron’s response under these conditions.

The computer simulations were carried out and analyzed by Bringa, Orlando Deluigi, a CONICET postdoctoral fellow at SIMAF, and Carlos Ruestes, a researcher at the Polytechnic University of Madrid (Spain) and a member of SIMAF until 2019. “The experiments allow us to achieve extraordinary conditions, but to understand what happens inside the material, it is necessary to observe the response at the atomic scale. Simulations using the Molecular Dynamics technique help to connect the experimental measurements with the microscopic mechanisms of iron deformation,” the scientist pointed out.

It is worth noting that the simulations carried out at the University of Mendoza anticipated the results of the experiment, which highlights the potential of virtual laboratories to complement complex experimental results.

The study reveals that iron subjected to high pressures undergoes a reorganization of its atoms that modifies its microstructure and affects its final mechanical behavior. This information allows for a better understanding of the dynamics of Earth’s inner core, composed of approximately 85 percent iron. The results are significant because they provide new data for understanding the internal dynamics of Earth and other similar planets.

“The ‘hardness’ of the Earth’s core determines the speed at which seismic waves travel through the planet, a parameter necessary for improving estimates of earthquake location and magnitude. This hardness also influences the mechanisms that generate the Earth’s magnetic field, as it modifies the mechanical and chemical coupling between the solid core and the surrounding liquid. Furthermore, it is key to understanding asteroid collisions and contributes to the study of other planets that may also have iron cores, one of the most common materials in the universe,” the scientist concluded.

The multidisciplinary work brought together researchers from Lawrence Livermore National Laboratory, University of California, San Diego; the Polytechnic University of Madrid; the SLAC National Accelerator Laboratory, Stanford University; and other collaborating institutions. The participation of CONICET, the University of Mendoza, and the Polytechnic University of Madrid reinforces the contribution of Ibero-American research to international studies on materials subjected to extreme conditions.

Citation
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KIM, YJ., et al. Dynamic strength of iron under pressure-temperature conditions of Earth’s inner core. Nature Communications , 2026, vol. 17. DOI: 10.1038/s41467-026-72210-4

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