We present measurements on Fe2O3 amorphization and melt under laser-driven shock compression up to 209(10) GPa via time-resolved in situ x-ray diffraction. At 122(3) GPa, a diffuse signal is observed indicating the presence of a non-crystalline phase. Structure factors have been extracted up to 182(6) GPa showing the presence of two well-defined peaks. A rapid change in the intensity ratio of the two peaks is identified between 145(10) and 151(10) GPa, indicative of a phase change. Present DFT+U calculations of temperatures along Fe2O3 Hugoniot are in agreement with SESAME 7440 and indicate relatively low temperatures, below 2000 K, up to 150 GPa. The non-crystalline diffuse scattering is thus consistent with the - as yet unreported - shock amorphization of Fe2O3 between 122(3) and 145(10) GPa, followed by an amorphous-to-liquid transition above 151(10) GPa. Upon release, a non-crystalline phase is observed alongside crystalline α-Fe2O3. The extracted structure factor and pair distribution function of this release phase resemble those reported for Fe2O3 melt at ambient pressure.
@article{arxiv.2408.17204,
title = {Shock-driven amorphization and melt in Fe$_2$O$_3$},
author = {Céline Crépisson and Alexis Amouretti and Marion Harmand and Chrystèle Sanloup and Patrick Heighway and Sam Azadi and David McGonegle and Thomas Campbell and David Alexander Chin and Ethan Smith and Linda Hansen and Alessandro Forte and Thomas Gawne and Hae Ja Lee and Bob Nagler and YuanFeng Shi and Guillaume Fiquet and François Guyot and Mikako Makita and Alessandra Benuzzi-Mounaix and Tommaso Vinci and Kohei Miyanishi and Norimasa Ozaki and Tatiana Pikuz and Hirotaka Nakamura and Keiichi Sueda and Toshinori Yabuuchi and Makina Yabashi and Justin S. Wark and Danae N. Polsin and Sam M. Vinko},
journal= {arXiv preprint arXiv:2408.17204},
year = {2025}
}