Sébastien Merkel

I'm in Japan! Attending the Onsen Workshop: Formation and Chemical Composition of Cores in the coming days and presenting some of our work on the ERC HotCores project. Nice to be back in Tokyo, it had been a while. 

The 2025 edition of the EHPRG Meeting was held September 1 to 5 in Manchester, United Kingdom, and I was offered to present a 1-hour keynote lecture on the iron phase diagram at multiple timescales. This was a nice opportunity to highlight our latest results on iron from the ERC HotCores project, obtained using advanced X-ray sources such as the European XFEL and the ESRF synchrotron.  

The 2025 SEES-ISRD Joint Meeting was held at the University of Chicago, United States, August 11-13, 2025, to discuss opportunities for using synchrotron radiation in Earth and Environmental Science as well as for In-situ Studies of Rock Deformation. I gave a keynote presentation on Multi-Grain Diffraction and Deformation Experiments in Diamond Anvil Cells and how the method could be useful for both these fields.

Sunshine on the French northern coast! The Earth and Planetary Materials group of the UMET lab in Lille met in the Univ. Lille Marine Station in Wimereux, on the Nortern Sea coastline, to discuss opportunities for the future of the team.

This 2025 EGU General Assembly was held in Vienna, Austria, 27 April–2 May 2025. I and ERC HotCores members organized the session GD 8.4, Earth and Planetary cores, with several presentations from the project. See you next year!

New paper! On the Influence of Pressure, Phase Transitions, and Water on Large-Scale Seismic Anisotropy Underneath a Subduction Zone published in AGU's Geochemistry, Geophysics, Geosystems. This paper of J.K. Magali is one of the last results of the ANR-DFG TIMEleSS project. In this work, we investigate how subduction in the upper mantle and transition zone influences the alignment of minerals making up the mantle, which in turn, affects the speed and direction of seismic waves known as seismic anisotropy.

The annual meeting of the AGU attracts over 25,000+ scientists, educators, policymakers, journalists and communicators from over 100 countries in the broad field of Earth and space sciences. In December 2024, I was in Washington DC to attend the 2024 AGU Meeting and present the latest results of our European Research Council HotCores project.

New paper! Measurement bias in self-heating x-ray free electron laser experiments from diffraction studies of phase transformation in titanium, published in the Journal of Applied Physics recently. In this work, we focus on the physics of X-ray self-heating. X-ray heating is a common by-product of X-ray Free Electron Laser (XFEL) techniques that can affect targets, optics, and other irradiated materials. It is also useful in a new family of high pressure experiments that can reach the pressure and temperatures of planetary interiors. The work is a result of a collaboration of 31 laboratories over 7 countries and 3 continents, led by student O.B. Ball and R. S. McWilliams at the University of Edinburgh.

Participating to ICOTOM in Metz this week, the International Conference on Textures of Material, where world experts come to meet and discuss the latest advances in textures and microstructures of materials, with applications in multiple classes of materials, from metals to the deep Earth.

Yet another publication in two days! Zinc is a hcp structure metal, with a very large c/a ratio at ambient pressure, which then decreases and crosses √3 at ~10 GPa. As a consequence, twinning in zinc is unusual and can change in nature, from compressive to tensile, depending on the external pressure. Want to know more? Have a look at our ERC HotCores paper: Androgynous {10⁢-1⁢2} twin in zinc, published today in Physical Review Materials.