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Crystallinity and Magnetoresistance in Calcium Doped Lanthanum Manganites

Published online by Cambridge University Press:  10 February 2011

E. S. Gillman
Affiliation:
Departments of Chemistry and Physics, Center for Materials Research and Technology - MARTECH, Florida State University, Tallahassee, FL 32306–3006, USA
K. H. Dahmen
Affiliation:
Departments of Chemistry and Physics, Center for Materials Research and Technology - MARTECH, Florida State University, Tallahassee, FL 32306–3006, USA
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Abstract

Thin films of calcium doped lanthanum manganites Lal-xCaxMnO3 (LCMO) with x ∼ 0.41 have been prepared on LaAlO3(001) (LAO) Y-stablized ZrO2(001) (YSZ), and Al2O3(0001) (SAP) substrates by liquid delivery metal-organic chemical vapor deposition (LD-MOCVD). The films on YSZ and SAP substrates have a textured, polycrystalline morphology with a preferred orientation of (110). The films on LAO show a single-crystalline morphology and a (100) orientation. Transport measurements show the polycrystalline films have a resistance peak approximately 60K lower than the films on LAO and, in general, have a much higher overall resistance. The magne-toresistance (MR) ratio ([R(H) - R(0)]/R(H)) is sharply peaked near the maximum in resistance for the films on LAO, while the polycrystalline films show a noticeable absence of this sharply peaked behavior and a flat, rather large (∼ 100%) MR ratio over a large temperature range. These results will be discussed in terms of grain boundary scattering, crystallite size, and magnetization.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

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References

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