Thermal stability of epitaxial SrRuO3 films as a function of oxygen pressure

Lee, Ho Nyung; Christen, H. M.; Chisholm, Matthew F.; Rouleau, Christopher M.; Lowndes, D. H.

doi:10.1063/1.1753650

Cited by 75 publications

(55 citation statements)

References 16 publications

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“…Similar planar defects, recognized as a double SrO layer, were discovered by Jia et al 35 at the BaTiO 3 / SrRuO 3 interface, formed at the temperature of 800°C and oxygen pressure of 2 ϫ 10 −3 mbar. Another case of a broadened interface on unknown composition between SrRuO 3 thin film and SrTiO 3 substrate was observed by Lee et al 36 Samples were high quality thin films deposited by PLD at 700°C and oxygen pressure of 0.13 mbar.…”

Section: -2mentioning

confidence: 96%

Surface layer of SrRuO3 epitaxial thin films under oxidizing and reducing conditions

Młynarczyk

Szot

Petraru

et al. 2007

Journal of Applied Physics

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Imperfect stoichiometry and heterogeneity of a surface layer of SrRuO3 epitaxial thin films, grown on SrTiO3 substrates, are presented with the help of various methods. Rutherford backscattering spectroscopy, x-ray photoemission spectroscopy (XPS), and time of flight secondary ion mass spectrometry are used to obtain information about the stoichiometry and uniformity of the SrRuO3 structure. The temperature of chemical decomposition is first determined for polycrystalline samples under different conditions using thermogravimetry analysis. Then the determined values are used for thin film annealings in high and low oxygen pressure ambients, namely, air, vacuum, and hydrogen. The surface deterioration of the thin film together with changes in its electronic structure is investigated. O1s and Sr3d core lines measured by XPS for as-made samples obviously consist of multiple components indicating different chemical surroundings of atoms. Thanks to different incident beam angle measurements it is possible to distinguish between interior and surface components. Valence band spectra of the interior of the film are consistent with theoretical calculations. After annealing, the ratio of the different components changes drastically. Stoichiometry near the surface changes, mostly due to ruthenium loss (RuOX) or a segregation process. The width and position of the Ru3p line for as-made samples suggest a mixed oxidation state from metallic to fully oxidized. Long annealing in hydrogen or vacuum ambient leads to a complete reduction of ruthenium to the metallic state. Local conductivity atomic force microscopy scans reveal the presence of nonconductive adsorbates incorporated in the surface region of the film. Charge transport in these measurements shows a tunneling character. Scanning tunneling microscopy scans show some loose and mobile adsorbates on the surface, likely containing hydroxyls. These results suggest that an adequate description of a SrRuO3 thin film should take into account imperfections and high reactivity of its surface region.

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Section: -2mentioning

confidence: 96%

Surface layer of SrRuO3 epitaxial thin films under oxidizing and reducing conditions

Młynarczyk

Szot

Petraru

et al. 2007

Journal of Applied Physics

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“…The electronic structure of SRO113 is located near to the half-metallicity as reported by density functional theory (DFT) + U calculations [15][16][17]. The thin film SRO113 is of particular interest as a widelyused bottom electrode [18][19][20] and is intensively studied for the possibility of a new field-effect device [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Quasiparticle self-consistent GW calculation of Sr2RuO4 and SrRuO3

et al. 2016

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Using quasiparticle self-consistent GW calculations, we re-examined the electronic structure of Sr2RuO4 and SrRuO3. Our calculations show that the correlation effects beyond the conventional LDA (local density approximation) and GGA (generalized gradient approximation) are reasonably well captured by QSGW self-energy without any ad hoc parameter or any ambiguity related to the double-counting and the downfolding issues. While the spectral weight transfer to the lower and upper Hubbard band is not observed, the noticeable bandwidth reduction and effective mass enhancement are obtained. Important features in the electronic structures that have been debated over the last decades such as the photoemission spectra at around −3 eV in Sr2RuO4 and the halfmetallicity for SrRuO3 are discussed in the light of our QSGW results and in comparison with the previous studies. The promising aspects of QSGW are highlighted as the first-principles calculation method to describe the moderately correlated 4d transition metal oxides along with its limitations.

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“…[1][2][3] In the perovskite crystal family ͑ABO 3 stoichiometry͒, the itinerant ferromagnetic SrRuO 3 ͑SRO͒ is a popular choice since it is one of the more conductive metallic oxides with good thermal properties. 4 In thin films, SRO is intensely investigated as a possible route to the realization of novel field-effect devices. 5,6 In addition, it is of particular interest to the spintronic 7,8 and multiferroic 9,10 communities, which have been recently energized by the possible device applications available from engineering interface phenomena.…”

Section: Introductionmentioning

confidence: 99%

Electronic properties of bulk and thin filmSrRuO3: Search for the metal-insulator transition

et al. 2008

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We calculate the properties of the 4d ferromagnet SrRuO 3 in bulk and thin film form with the aim of understanding the experimentally observed metal-to-insulator transition at reduced thickness. Although the spatial extent of the 4d orbitals is quite large, many experimental results have suggested that electron-electron correlations play an important role in determining this material's electronic structure. In order to investigate the importance of correlation, we use two approaches which go beyond the conventional local-density approximation to density-functional theory ͑DFT͒: the local spin-density approximation+ Hubbard U ͑LSDA+ U͒ and the pseudopotential self-interaction correction ͑pseudo-SIC͒ methods. We find that the details of the electronic structure predicted with the LSDA do not agree with the experimental spectroscopic data for bulk and thin film SrRuO 3 . Improvement is found by including electron-electron correlations, and we suggest that bulk orthorhombic SrRuO 3 is a moderately correlated ferromagnet whose electronic structure is best described by a 0.6 eV on-site Hubbard term, or equivalently with corrections for the self-interaction error. We also perform ab initio transport calculations that confirm that SrRuO 3 has a negative spin polarization at the Fermi level, due to the position of the minority Ru 4d band center. Even with static correlations included in our calculations we are unable to reproduce the experimentally observed metal-insulator transition, suggesting that the electronic behavior of SrRuO 3 ultrathin films might be dominated by extrinsic factors, such as surface disorder and defects, or due to dynamic spin correlations which are not included in our theoretical methods.

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Thermal stability of epitaxial SrRuO3 films as a function of oxygen pressure

Abstract: Epitaxial growth and strain relaxation of MgO thin films on Si grown by molecular beam epitaxyDependence of crystallinity on oxygen pressure and growth mode of La 0.3 Sr 1.7 AlTaO 6 thin films on different substrates

Cited by 75 publications

References 16 publications

Surface layer of SrRuO3 epitaxial thin films under oxidizing and reducing conditions

Surface layer of SrRuO3 epitaxial thin films under oxidizing and reducing conditions

Quasiparticle self-consistent GW calculation of Sr2RuO4 and SrRuO3

Electronic properties of bulk and thin filmSrRuO3: Search for the metal-insulator transition

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