Back to Search Start Over

[Untitled]

Authors :
Susanne Stemmer
Nigel D. Browning
Stephen K. Streiffer
Angus I. Kingon
Cem Basceri
Source :
Interface Science. 8:209-221
Publication Year :
2000
Publisher :
Springer Science and Business Media LLC, 2000.

Abstract

In this paper, we investigate the role of grain boundaries in polycrystalline (Ba x Sr1−x )Ti1+y O3+z films, grown by metal organic vapor deposition, in the accommodation of nonstoichiometry, as well as their role in the strong composition dependence of the electric and dielectric behavior observed in these films. High-spatial resolution electron energy-loss spectroscopy is used for the analysis of composition and structural changes at grain boundaries, as a function of film composition. The existence of amorphous, titanium rich, TiO2-like phases at the grain boundaries of films with large amounts of excess Ti (y ≥ 0.08) may explain the non-monotonic resistance degradation behavior of the films as a function of Ti content. However, we show that a grain boundary phase model fails to explain the strong composition dependence of the dielectric behavior. Electron energy-loss spectra indicate a distortion of the Ti–O octahedra in the grain interiors in samples with increasing Ti excess. The decrease of the dielectric constant with increasing amounts of excess Ti is therefore more likely due to Ti accommodation in the grain interiors.

Details

ISSN :
09277056
Volume :
8
Database :
OpenAIRE
Journal :
Interface Science
Accession number :
edsair.doi...........28a6b4e72accfa538cb6d5f074202758
Full Text :
https://doi.org/10.1023/a:1008794520909