Cation non-stoichiometry in pulsed laser deposited Sr{sub 2+y}Fe{sub 1+x}Mo{sub 1-x}O₆ epitaxial films

Journal Article · Mon Jul 07 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4885450· OSTI ID:22306247

Meyer, T. L.; Dixit, M.; Williams, R. E. A.; Susner, M. A.; Fraser, H. L.; McComb, D. W.; Sumption, M. D. ^[1]; Lemberger, T. R. ^[2]

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1. Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210-1117 (United States)
2. Department of Physics, The Ohio State University, Columbus, Ohio 43210-1117 (United States)

Sr₂FeMoO₆ (SFMO) films were grown on SrTiO₃ (100)- and (111)-oriented substrates via pulsed laser deposition (PLD). In order to study the fundamental characteristics of deposition, films were grown in two different PLD chambers. In chamber I, the best films were grown with a relatively long substrate-to-target distance (89 mm), high substrate temperature (850 °C), and low pressure (50 mTorr) in a 95% Ar/5% H₂ atmosphere. Although X-ray diffraction (XRD) measurements indicate these films are single phase, Rutherford Backscattering (RBS) measurements reveal considerable non-stoichiometry, corresponding to a Sr₂Fe{sub 1–x}Mo{sub 1+x}O₆ composition with x≅0.2–0.3. This level of non-stoichiometry results in inferior magnetic properties. In chamber II, the best films were grown with a much shorter substrate-to-target distance (38 mm), lower temperature (680 °C), and higher pressure (225 mTorr). XRD measurements show that the films are single phase, and RBS measurements indicate that they are nearly stoichiometric. The degree of ordering between Fe and Mo was dependent on both the temperature and pressure used during deposition, reaching a maximum order parameter of 85%. The saturation magnetization increases as the Fe/Mo ordering increases, reaching a maximum of 2.4 μ_B/f.u. Based on prior studies of bulk samples, one would expect a higher saturation magnetization for this degree of Fe/Mo order. The presence of extra strontium oxide layers in the form of Ruddlesden-Popper intergrowths appears to be responsible for the lower than expected saturation magnetization of these films.

• OSTI ID: 22306247
• Journal Information: Journal of Applied Physics, Vol. 116, Issue 1; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ENERGY BEAM DEPOSITION
EPITAXY
FILMS
IRON COMPOUNDS
LASER RADIATION
LAYERS
MAGNETIC PROPERTIES
MAGNETIZATION
MOLYBDATES
RUTHERFORD BACKSCATTERING SPECTROSCOPY
SATURATION
STOICHIOMETRY
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
STRONTIUM TITANATES
SUBSTRATES
X-RAY DIFFRACTION