Investigation of orthorhombic perovskite La1-xCaxFeO3-y (0 ⩽ x ⩽ 0.50)
- 1 January 1992
- journal article
- Published by IOP Publishing in Physica Scripta
- Vol. 45 (1) , 62-64
- https://doi.org/10.1088/0031-8949/45/1/011
Abstract
La1-xCaxFeO3-y compounds (0 ≤ x ≤ 0.50) have been synthesized and investigated by means of X-ray diffraction and Mössbauer spectroscopy. A linear decrease of the lattice constants of the orthorhombic perovskite with increasing x is found and explained as being partially due to the influence of the increasing valence of iron with increasing x on the ion radius of iron and on the cell dimension. The gradual decrease of isomer shift at room temperature with increasing x arises from the gradually increasing average intermediate valence state of iron due likely to electron hopping not necessarily between paired Fe3+ and Fe4+ but among iron ions mixed in any Fe3+/Fe4+ ratio on identical crystal sites. At low temperature, Fe4+ ions disproportionate into Fe3+ and Fe5+ ions.Keywords
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