Europhys. Lett.
Volume 71, Number 2, July 2005
Page(s) 228 - 234
Section Condensed matter: structural, mechanical and thermal properties
Published online 08 June 2005
Europhys. Lett., 71 (2), pp. 228-234 (2005)
DOI: 10.1209/epl/i2005-10071-9

Consequences of pressure-instigated spin crossover in R $\chem{FeO_3}$ perovskites; a volume collapse with no symmetry modification

G. Kh. Rozenberg1, M. P. Pasternak1, W. M. Xu1, L. S. Dubrovinsky2, S. Carlson3 and R. D. Taylor4

1  School of Physics and Astronomy, Tel-Aviv University - Tel-Aviv, Israel
2  Bayerisches Geoinstitut, University Bayreuth - Bayreuth, Germany
3  European Synchrotron Radiation Facility - Grenoble, France
4  MST-10, Los Alamos National Laboratory - Los Alamos, NM 87545, USA

received 3 March 2005; accepted in final form 11 May 2005
published online 8 June 2005

High-pressure X-ray diffraction, Mössbauer, and Raman studies in the antiferromagnetic insulators R $\chem{FeO_3}$ orthorhombic perovskites ( $R={\rm Pr}$, $\chem{Eu}$, $\chem{Lu}$) disclose an unusual phenomena of a reversible first-order isostructural phase transition around 50$\un{GPa}$ concurring with an abrupt $\sim 5\%$ volume decrease. It is shown experimentally that this transformation concurs with, and is driven by, a high-to-low-spin transition taking place in $\chem{Fe^{3+}}$; a manifestation of a new kind of isostructural phase transition. These studies suggest that the R $\chem{FeO_3}$ perovskite is a rather sturdy oxide-structure, maintaining its original structural symmetry beyond 125$\un{GPa}$.

61.10.-i - X-ray diffraction and scattering.
62.50.+p - High-pressure and shock wave effects in solids and liquids.
76.80.+y - Mössbauer effect; other $\gamma$-ray spectroscopy.

© EDP Sciences 2005