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Vacancy Related Defects in La0.5Sr0.5CoO3-δ Thin Films

Published online by Cambridge University Press:  15 February 2011

D. J. Keeble ,
S. Madhukar ,
B. Nielsen ,
A. Krishnan ,
P. Asoka-Kumar ,
S. Aggarwal ,
R. Ramesh  and
E. H. Poindexter
D. J. Keeble
Affiliation:
Carnegie Laboratory of Physics, University of Dundee, Dundee DD1 4HN, UK
S. Madhukar
Affiliation:
Department of Materials Science and Nuclear Engineering, University of Maryland, MD 20742
B. Nielsen
Affiliation:
Brookhaven National Laboratory, Upton, NY 11793
A. Krishnan
Affiliation:
Department of Physics, Michigan Technological University, Houghton MI 49931
P. Asoka-Kumar
Affiliation:
Brookhaven National Laboratory, Upton, NY 11793
S. Aggarwal
Affiliation:
Department of Materials Science and Nuclear Engineering, University of Maryland, MD 20742
R. Ramesh
Affiliation:
Department of Materials Science and Nuclear Engineering, University of Maryland, MD 20742
E. H. Poindexter
Affiliation:
Army Research Laboratory, Adelphi, MD 20783
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Abstract

Laser ablated La0.5Sr0.5CoO3-δ thin films have been studied by Doppler-broademng-detected positron annihilation using a variable-energy positron beam. The oxygen partial pressure during cooling from the growth temperature was altered through the range 760 torr to 10−5 torr to change the oxygen non-stoichiometry of the films.

The measured Doppler broadened lineshape parameter S was found to increase with increasing oxygen nonstoichiometry. For films cooled with an oxygen partial pressure of ≤ 10−4 Torr positron trapping to monovacancy type defects is infered. It is proposed that Sr ion oxygen vacancy complexes are likely trapping sites.

For the film cooled in 10−5 torr oxygen the magnitude of the increase in S, with respect to that measured from the film cooled in 760 Torr oxygen, showed positron trapping to vacancy cluster defects is occuring.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 474: Symposium L – Epitaxial Oxide Thin Films III , 1997 , 229
Copyright
Copyright © Materials Research Society 1997

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References

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