[Zurück]

T. Götsch, N. Köpfle, L. Schlicker, E. Carbonio, M. Hävecker, A. Knop-Gericke, R. Schlögl, M. Bekheet, A. Gurlo, A. Doran, J. Bernardi, B. Klötzer, S. Penner:
"Treading in the Limited Stability Regime of Lanthanum Strontium Ferrite - Reduction, Phase Change and Exsolution";
ECS Transactions, 91 (2019), 1; S. 1771 - 1781.

We present an in situ investigation of the iron exsolution from
lanthanum strontium ferrite perovskites. Using in situ X-ray
diffraction experiments at the synchrotron, the exact onset of
exsolution was determined by a change in the lattice parameter
before any iron reflexes become visible. For an initially
orthorhombic thin film, on the other hand, a phase transition to a
fluorite/rock-salt structure is observed to occur during the
exsolution. Also, a difference in the iron oxidation states between
bulk and surface is found since photoelectron spectroscopy and Xray
absorption spectroscopy both indicate the existence of the
Fe(III)/Fe(II) couple in oxidation/reduction cycles, whereas
magnetic measurements would suggest Fe(IV)/Fe(III).

http://dx.doi.org/10.1149/09101.1771ecst