학술논문
Phase transitions of Fe$_2$O$_3$ under laser shock compression
Document Type
Working Paper
Author
Amouretti, A.; Crépisson, C.; Azadi, S.; Cabaret, D.; Campbell, T.; Chin, D. A.; Colin, B.; Collins, G. R.; Crandall, L.; Fiquet, G.; Forte, A.; Gawne, T.; Guyot, F.; Heighway, P.; Lee, H.; McGonegle, D.; Nagler, B.; Pintor, J.; Polsin, D.; Rousse, G.; Shi, Y.; Smith, E.; Wark, J. S.; Vinko, S. M.; Harmand, M.
Source
Subject
Language
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 $\alpha$-Fe$_2$O$_3$ to a new $\alpha^\prime$-Fe$_2$O$_3$ phase at a pressure of 50-62 GPa. The $\alpha^\prime$-Fe$_2$O$_3$ phase differs from $\alpha$-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 $\alpha$ and $\alpha^\prime$ 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.
Comment: 7 pages, 5 figures
Comment: 7 pages, 5 figures