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Mn Valency at La0.7Sr0.3MnO3/SrTiO3 (0 0 1) Thin Film Interfaces

Published online by Cambridge University Press:  22 May 2009

Thomas Riedl ,
Thomas Gemming ,
Kathrin Dörr ,
Martina Luysberg  and
Klaus Wetzig
Thomas Riedl
Affiliation:
IFW Dresden, PF 270116, 01171 Dresden, Germany
Thomas Gemming*
Affiliation:
IFW Dresden, PF 270116, 01171 Dresden, Germany
Kathrin Dörr
Affiliation:
IFW Dresden, PF 270116, 01171 Dresden, Germany
Martina Luysberg
Affiliation:
Institut für Festkörperforschung and Ernst Ruska Centrum, Forschungszentrum Jülich, 52425 Jülich, Germany
Klaus Wetzig
Affiliation:
IFW Dresden, PF 270116, 01171 Dresden, Germany
*
Corresponding author. E-mail: T.Gemming@ifw-dresden.de
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Abstract

This article presents a (scanning) transmission electron microscopy (TEM) study of Mn valency and its structural origin at La0.7Sr0.3MnO3/SrTiO3(0 0 1) thin film interfaces. Mn valency deviations can lead to a breakdown of ferromagnetic order and thus lower the tunneling magnetoresistance of tunnel junctions. Here, at the interface, a Mn valency reduction of 0.16 ± 0.10 compared to the film interior and an additional feature at the low energy-loss flank of the Mn-L3 line have been observed. The latter may be attributed to an elongation of the (0 0 1) plane spacing at the interface detected by geometrical phase analysis of high-resolution images. Regarding the interface geometry, high-resolution high-angle annular dark-field scanning TEM images reveal an atomically sharp interface in some regions whereas the transition appears broadened in others. This can be explained by the presence of steps. The performed measurements indicate that, among the various structure-related influences on the valency, the atomic layer termination and the local oxygen content are most important.

Keywords

Mn valencyelectron energy-loss spectroscopynear-edge fine structurescanning/transmission electron microscopyinterface structureperovskites
Type
Materials Applications
Information
Microscopy and Microanalysis , Volume 15 , Issue 3 , June 2009 , pp. 213 - 221
Copyright
Copyright © Microscopy Society of America 2009

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References

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