X-ray absorption fine structure studies of Mn coordination in doped perovskite SrTiO3

The coordination of Mn in doped SrTiO3 ceramics having nominal compositions SrTi0.98Mn0.02O3 and Sr0.98Mn0.02TiO3 was analyzed using x-ray absorption fine structure (XAFS) measurements. As expected, Mn4+ substitution for Ti4+ leads to Mn occupancy of the octahedral B-sites of ABO3 perovskite lattice...

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Veröffentlicht in:Applied physics letters 2010-02, Vol.96 (5)
Hauptverfasser: Levin, I., Krayzman, V., Woicik, J. C., Tkach, A., Vilarinho, P. M.
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Sprache:eng
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Zusammenfassung:The coordination of Mn in doped SrTiO3 ceramics having nominal compositions SrTi0.98Mn0.02O3 and Sr0.98Mn0.02TiO3 was analyzed using x-ray absorption fine structure (XAFS) measurements. As expected, Mn4+ substitution for Ti4+ leads to Mn occupancy of the octahedral B-sites of ABO3 perovskite lattice with a Mn–O bond distance of 1.902 Å (compared to 1.953 Å for Ti–O) and no significant local distortions around the Mn atoms. In contrast, for the composition Sr0.98Mn0.02TiO3, Mn segregates to both the A-sites (as Mn2+) and the B-sites (predominantly as Mn4+). Extended XAFS confirms strong (≈0.77 Å) displacements of Mn2+ cations off the ideal A-site positions along ⟨001⟩ directions with a significant distortion of several coordination shells around the dopant atoms.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.3298369