Isostructural phase transition of Fe2O3 under laser shock compression

Journal article

We present in situ x-ray diffraction and velocity measurements of Fe2⁢O3 under laser shock compression at pressures between 38–122 GPa. None of the high-pressure phases reported by static compression studies were observed. Instead, we observed an isostructural phase transition from 𝛼−Fe2⁢O3 to a new 𝛼′−Fe2⁢O3 phase at a pressure of 50–62 GPa. The 𝛼′−Fe2⁢O3 phase differs from 𝛼−Fe2⁢O3 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 𝛼 and 𝛼′ 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.

Authors: Amouretti, A; Crepisson, C; Azadi, S; Brisset, F; Cabaret, D

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Physical Society
• Journal: Physical Review Letters
• Volume: 134
• Issue: 17
• Article number: 176102
• Publication date: 2025-04-30
• Acceptance date: 2025-03-09
• DOI: 10.1103/PhysRevLett.134.176102
• EISSN: 1079-7114
• ISSN: 0031-9007
• Language: English