Structural, magnetic and optical properties of Y bFe{sub 2}O{sub 4} films deposited by spin coating

Journal Article · Mon Aug 15 00:00:00 EDT 2016 · AIP Advances

DOI:https://doi.org/10.1063/1.4961639· OSTI ID:22611391

Fujii, Tatsuo; Okamura, Naoya; Hashimoto, Hideki; Nakanishi, Makoto ^[1]; Kano, Jun ^[1]; Ikeda, Naoshi ^[2]

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1. Department of Applied Chemistry, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530 (Japan)
2. Department of Physics, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530 (Japan)

Rare-earth iron oxides (RFe{sub 2}O{sub 4}) have attracting attention as new electronic device materials because of their numerous functionalities, such as electronic ferroelectricity, ferrimagnetism, and high infrared absorption. In this paper, nearly monophasic Y bFe{sub 2}O{sub 4} films were prepared on α-Al{sub 2}O{sub 3}(001) substrates by the spin coating method using an aqueous-based Y bFe{sub 2}O{sub 4} solution. The solution was composed of a stoichiometric ratio of Y b(CH{sub 3}COO){sub 3} and Fe(NO{sub 3}){sub 3} with excess chelating agents. After heat treatment above 800 °C, well-crystallized and highly (001)-oriented Y bFe{sub 2}O{sub 4} started to epitaxially form on the substrate under controlled oxygen partial pressure with H{sub 2}/CO{sub 2} gas mixtures. X-ray pole figure analysis confirmed the following epitaxial relationship: Y bFe{sub 2}O{sub 4}[100](001)//α-Al{sub 2}O{sub 3}[100](001). Moreover formation of an Fe{sub 3}O{sub 4} interracial layer between Y bFe{sub 2}O{sub 4} and α-Al{sub 2}O{sub 3} was detected by high-resolution transmission electron microscopy. Presence of the Fe{sub 3}O{sub 4} interracial layer seemed to release the lattice misfit with the substrate. The Fe{sup 2+}/Fe{sup 3+} ratio in the obtained Y bFe{sub 2}O{sub 4} films was nearly stoichiometric and the indirect bandgap assigned to Fe{sup 2+} → Fe{sup 3+} charge transfer excitation was found to be ∼0.4 eV by optical spectroscopy. A clear magnetic transition from the paramagnetic state to the ferrimagnetic state occurred at ∼230 K.

• OSTI ID: 22611391
• Journal Information: AIP Advances, Vol. 6, Issue 8; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 2158-3226
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM OXIDES
CARBON DIOXIDE
CRYSTAL STRUCTURE
EXCITATION
FERRIMAGNETISM
FERRITES
FILMS
HEAT TREATMENTS
IRON NITRATES
LAYERS
MAGNETIC PROPERTIES
NITROGEN OXIDES
OPTICAL PROPERTIES
PARAMAGNETISM
RARE EARTH COMPOUNDS
SPECTROSCOPY
SPIN-ON COATING
STOICHIOMETRY
SUBSTRATES
TRANSMISSION ELECTRON MICROSCOPY