High-pressure behavior of perovskite: FeTiO_{3} dissociation into (Fe_{1-delta},Ti_{delta})O and Fe_{1+delta}Ti_{2-delta}O_{5}.
The stability of perovskite-structured materials at high pressure and temperature is of fundamental interest in solid-state physics, chemistry, and the geosciences. As an alternative to decomposition into oxides or transformation of the CaIrO_{3} postperovskite structure, we observe in situ the breakdown of FeTiO_{3} perovskite into a (Fe_{1-delta},Ti_{delta})O + Fe_{1+delta}Ti_{2-delta}O_{5} assemblage beyond 53 GPa and 2000 K. The high-pressure high-temperature phase of Fe_{1+delta}Ti_{2-delta}O_{5} with a new structure (space group C2/c) could be preserved on decompression to 9 GPa, and amorphizes under further pressure release. Our study demonstrates that perovskite-structured materials can undergo chemical changes and form complex oxides with new structures, rather than only transform to denser polymorphs or decompose to simple oxides.
Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth D-95440, Germany.
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X
Wu
G
G
Steinle-Neumann
O
O
Narygina
I
I
Kantor
C
C
McCammon
V
V
Prakapenka
V
V
Swamy
L
L
Dubrovinsky