# Chang'e-6 impact glass from the South Pole-Aitken Basin contains nanoscale γ-Fe particles

- Published: 2026-11-10 18:34 UTC
- Section: Sky & Space › Astronomy
- Tags: Chang'e-6 samples, γ-Fe on the Moon, lunar impact glass, South Pole-Aitken Basin, magnetic vortex state, electron holography, lunar remanent magnetization, lunar core dynamo, iron nanoparticles, Hefei Institutes of Physical Science
- URL: https://realtech.media/news/rt-7f05d92fc74d184dc224cdd3_chang_e_6/

**Chinese researchers found γ-Fe, a high-temperature iron phase not previously documented in lunar samples, preserved at ambient temperature as nanoparticles with a magnetic vortex state.**

![Chang'e-6 impact glass from the South Pole-Aitken Basin contains nanoscale γ-Fe particles](https://realtech.media/media/2026/11/37e579d560f1e113.jpg)
*Eugene A. CernanPhotomontage by User:Grunpfnul, Wikimedia Commons, Public domain*

A team led by Prof. Haifeng Du of the High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, has identified face-centered cubic γ-Fe in impact glass fragments from the Chang'e-6 samples. The material comes from the South Pole-Aitken Basin on the Moon. The results were published on 16 September in the journal Proceedings of the National Academy of Sciences. The iron is present as nanometer-scale particles that are stable at ambient temperature [1].

## A phase of iron not seen before in lunar samples

On the lunar surface, α-Fe and Fe-Ni alloys are widespread and are the dominant carriers of remanent magnetization. Metallic γ-Fe, by contrast, is stable only at high temperatures and had not been documented in lunar samples [1]. Under normal conditions it transforms into α-Fe as the temperature falls.

The researchers prepared the samples by focused ion beam and examined them with transmission electron microscopy and chemical analysis. In the two glass samples studied, γ-Fe was the dominant iron phase [1]. The authors propose that its formation and preservation at lunar surface temperature require trace γ-phase-stabilizing elements together with extremely rapid quenching during impacts [1]. According to the team, small amounts of carbon and other elements and the surrounding glassy matrix may also have helped retain the crystal structure.

## Magnetic vortex state in individual particles

To test whether the particles can hold magnetic information, the group used off-axis electron holography, a technique that maps magnetic fields at very small scales. Electron holography showed that the γ-Fe particles have a magnetic vortex domain state [1]. Relatively large particles displayed a stable single-vortex state, with magnetization arranged in a circulating pattern, and kept a stable magnetic response in an external magnetic field.

The Moon no longer has a global magnetic field, but its rocks and soils contain magnetic minerals that can record past conditions. The authors say the findings provide a basis for understanding the evolution of the lunar core dynamo and the mechanisms of impact-induced magnetic recording [1]. Because γ-Fe and α-Fe form under different conditions and have distinct magnetic properties, they may preserve records from different stages of impact events. Dr. Long Li of the institute, a member of the team, called the particles a "tiny magnetic fossil". The researchers note that further work is needed to establish how reliably these minerals preserve ancient magnetic signals.

## Sources

1. [Proceedings of the National Academy of Sciences](https://doi.org/10.1073/pnas.2608395123)
2. [SciTechDaily](https://scitechdaily.com/scientists-discover-a-strange-form-of-iron-on-the-moon-that-shouldnt-be-there)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-7f05d92fc74d184dc224cdd3_chang_e_6/