paper

Phase transitions of Fe $_{2}$ O $_{3}$ under laser shock compression

arXiv:2402.18432 · doi:10.1103/PhysRevLett.134.176102

Abstract

We present in-situ x-ray diffraction and velocity measurements of Fe $_{2}$ O $_{3}$ under laser shock compression at pressures between 38-116 GPa. None of the phases reported by static compression studies were observed. Instead, we observed an isostructural phase transition from $I^\pm$ -Fe $_{2}$ O $_{3}$ to a new $I^\pm^{'}$ -Fe $_{2}$ O $_{3}$ phase at a pressure of 50-62 GPa. The $I^\pm^{'}$ -Fe $_{2}$ O $_{3}$ phase differs from $I^\pm$ -Fe $_{2}$ O $_{3}$ by an 11% volume drop and a different unit cell compressibility. We further observed a two-wave structure in the velocity profile, which can be related to an intermediate regime where both $I^\pm$ and $I^\pm^{'}$ phases coexist. Density functional theory calculations with a Hubbard parameter indicate that the observed unit cell volume drop can be associated with a spin transition following a magnetic collapse.

7 pages, 5 figures

Phase transitions of Fe2​O3​ under laser shock compression

Abstract

Phase transitions of Fe $_{2}$ O $_{3}$ under laser shock compression