Interfacial structure and chemistry of epitaxial CoFe2O 4 thin films on SrTiO3 and MgO substrates

S. Xie; J. Cheng; B. W. Wessels; V. P. Dravid

doi:10.1063/1.3006060

Interfacial structure and chemistry of epitaxial CoFe₂O ₄ thin films on SrTiO₃ and MgO substrates

S. Xie^*, J. Cheng, B. W. Wessels, V. P. Dravid

^*Corresponding author for this work

Materials Science and Engineering

Research output: Contribution to journal › Article › peer-review

42 Scopus citations

Abstract

Interfacial structure and chemistry of epitaxial CoFe₂O ₄ thin films on (001)_SrTiO₃ and (001)_MgO substrates were investigated using high-angle-annular-dark-field imaging combined with electron-energy-loss-spectra (EELSs) analyses at a subnanometer scale. The results show that CoFe₂O₄ / SrTiO₃ interface is semicoherent with requisite dislocation density to accommodate ∼7% lattice mismatch, while the small (∼0.3%) lattice mismatch renders CoFe ₂O₄ /MgO interface coherent. EELS indicates that Fe valence is nominally +3, with no measurable change across the interfaces. Structural characterization corroborates with observed lower saturation magnetization of CoFe₂O₄ on MgO, which is a consequence of tensile stress built up in the 〈 100 〉 -direction negative magnetostrictive CoFe₂O₄.

Original language	English (US)
Article number	181901
Journal	Applied Physics Letters
Volume	93
Issue number	18
DOIs	https://doi.org/10.1063/1.3006060
State	Published - 2008

ASJC Scopus subject areas

Physics and Astronomy (miscellaneous)

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title = "Interfacial structure and chemistry of epitaxial CoFe2O 4 thin films on SrTiO3 and MgO substrates",

abstract = "Interfacial structure and chemistry of epitaxial CoFe2O 4 thin films on (001)_SrTiO3 and (001)_MgO substrates were investigated using high-angle-annular-dark-field imaging combined with electron-energy-loss-spectra (EELSs) analyses at a subnanometer scale. The results show that CoFe2O4 / SrTiO3 interface is semicoherent with requisite dislocation density to accommodate ∼7% lattice mismatch, while the small (∼0.3%) lattice mismatch renders CoFe 2O4 /MgO interface coherent. EELS indicates that Fe valence is nominally +3, with no measurable change across the interfaces. Structural characterization corroborates with observed lower saturation magnetization of CoFe2O4 on MgO, which is a consequence of tensile stress built up in the 〈 100 〉 -direction negative magnetostrictive CoFe2O4.",

author = "S. Xie and J. Cheng and Wessels, {B. W.} and Dravid, {V. P.}",

note = "Funding Information: The thin-film growth work was supported by the NSF under Grant Nos. DMR-0076097 and DMR-0511523 and Argonne National Laboratory by the U.S. Department of Energy, Office of Science and Office of Basic Energy Sciences under Contract No. W-31-109-Eng-38. The microscopy research was supported by the MRSEC Program of the National Science Foundation (Grant No. DMR-0520513) at the Materials Research Center of Northwestern University and was performed at the EPIC facility of NUANCE Center at Northwestern University. NUANCE Center is supported by NSF-NSEC, NSF-MRSEC, Keck Foundation, the State of Illinois, and Northwestern University.",

year = "2008",

doi = "10.1063/1.3006060",

language = "English (US)",

volume = "93",

journal = "Applied Physics Letters",

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AU - Dravid, V. P.

N1 - Funding Information: The thin-film growth work was supported by the NSF under Grant Nos. DMR-0076097 and DMR-0511523 and Argonne National Laboratory by the U.S. Department of Energy, Office of Science and Office of Basic Energy Sciences under Contract No. W-31-109-Eng-38. The microscopy research was supported by the MRSEC Program of the National Science Foundation (Grant No. DMR-0520513) at the Materials Research Center of Northwestern University and was performed at the EPIC facility of NUANCE Center at Northwestern University. NUANCE Center is supported by NSF-NSEC, NSF-MRSEC, Keck Foundation, the State of Illinois, and Northwestern University.

PY - 2008

Y1 - 2008

N2 - Interfacial structure and chemistry of epitaxial CoFe2O 4 thin films on (001)_SrTiO3 and (001)_MgO substrates were investigated using high-angle-annular-dark-field imaging combined with electron-energy-loss-spectra (EELSs) analyses at a subnanometer scale. The results show that CoFe2O4 / SrTiO3 interface is semicoherent with requisite dislocation density to accommodate ∼7% lattice mismatch, while the small (∼0.3%) lattice mismatch renders CoFe 2O4 /MgO interface coherent. EELS indicates that Fe valence is nominally +3, with no measurable change across the interfaces. Structural characterization corroborates with observed lower saturation magnetization of CoFe2O4 on MgO, which is a consequence of tensile stress built up in the 〈 100 〉 -direction negative magnetostrictive CoFe2O4.

AB - Interfacial structure and chemistry of epitaxial CoFe2O 4 thin films on (001)_SrTiO3 and (001)_MgO substrates were investigated using high-angle-annular-dark-field imaging combined with electron-energy-loss-spectra (EELSs) analyses at a subnanometer scale. The results show that CoFe2O4 / SrTiO3 interface is semicoherent with requisite dislocation density to accommodate ∼7% lattice mismatch, while the small (∼0.3%) lattice mismatch renders CoFe 2O4 /MgO interface coherent. EELS indicates that Fe valence is nominally +3, with no measurable change across the interfaces. Structural characterization corroborates with observed lower saturation magnetization of CoFe2O4 on MgO, which is a consequence of tensile stress built up in the 〈 100 〉 -direction negative magnetostrictive CoFe2O4.

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Interfacial structure and chemistry of epitaxial CoFe₂O ₄ thin films on SrTiO₃ and MgO substrates

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