<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mi>LaCo</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mi>n</mml:mi></mml:msub><mml:mo>/</mml:mo><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mi>SrCo</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>2.5</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow>

Noh, Su Jung; Ahn, Gihyeon; Seo, Ji Hoon; Gai, Zheng; Lee, Ho Nyung; Choi, Woo Seok; Moon, Sun-Young

doi:10.1103/physrevb.100.064415

Cited by 10 publications

(7 citation statements)

References 31 publications

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“…Moreover, strain gradient originating from gradual distribution of oxygen vacancies results in flexoelectricity and potentially enhances piezoelectricity in SrMnO 3 /(LaAlO 3 ) 0.3 (Sr 2 AlTaO 6 ) 0.7 . In summary, in the past several years, more and more studies have shown that by modulating oxygen vacancy behaviors, specific properties of oxide films could be enhanced or fabricated. − …”

Section: Introductionmentioning

confidence: 99%

Thickness Dependence of Oxygen Vacancy Ordering in Strained LaCoO_3–x Thin Films

et al. 2020

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The physical properties of perovskite oxides are very sensitive to oxygen vacancy structures, and an unambiguous acquaintance of vacancy structures of thin films is the precondition for applications of many functional devices. Here, we report critical thickness control over oxygen vacancy ordering structure in epitaxial LaCoO 3−x (LCO) thin films characterized by atomic resolution scanning transmission electron microscopy (STEM). Lattice mappings extracted from Cs-corrected STEM images demonstrate that vacancy ordering planes are vertically distributed in LCO films grown on SrTiO 3 substrates with the thickness above 5 nm, transversally distributed when the thickness is below 5 nm and distributed in a mixed manner when the thickness is 5 nm. Similar phenomenon also happens in LCO/NdGaO 3 film systems with the critical thickness of around 13 nm due to the reduced tensile strain imposed by the substrate. The thickness effect phenomenon is collaborated by first-principles calculations and the formation mechanism is discussed from the point of view of strain relaxation. These findings demonstrate that the thickness can exquisitely control the periodic modulations of vacancy ordering structure in LCO thin films, suggesting an effective pathway of thickness controlling and enhancing physical properties of functional oxide films.

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Section: Introductionmentioning

confidence: 99%

Thickness Dependence of Oxygen Vacancy Ordering in Strained LaCoO_3–x Thin Films

et al. 2020

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“…Advances in atomic-scale functional oxide film epitaxial growth have made it possible to control the structure and properties of materials through heterogeneous interfaces. The broken symmetry brought by the interface has led to the discovery of a large number of abnormal physical phenomena, such as two-dimensional electron gas, − interface superconductivity, fractional quantum hall effect, , topological insulator, and magnetoelectric coupling. , The coupling between different degrees of freedom on both sides of the interface, such as spin, orbit, charge, and lattice, produces a lot of abnormal physical properties on the interface. − Interfaces can also affect the structure and properties away from the interface. For example, some studies discovered the interaction between ferroelectric domain walls and defects at the interfaces is induced by different interface conditions …”

Section: Introductionmentioning

confidence: 99%

“…Recently, electrochemical gating is widely used as a new method for the control of functional materials, for example, Lu et al have shown that by changing the voltage, they can control tristate phase transformation and oxygen vacancy ordering during ionic liquid gating, Parkin and co-workers discovered that oxygen vacancy ordering can be controlled via ionic liquid gating . For the control of oxygen vacancy ordering in LaSrCoO 3– x , LaCoO 3– x (LCO), SrCoO 3– x , and so forth, researchers are showing more and more interest. − ,,,− We propose that oxygen vacancy ordering can be controlled by designing different interface boundary conditions.…”

Section: Introductionmentioning

confidence: 99%

Interface Engineering of Oxygen Vacancy Ordering in an Oxide Superlattice

et al. 2022

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Symmetry breaking induced by interfaces may produce abundant abnormal physical phenomena. The novel phenomena generated by these interfaces inspire people to explore the physics of oxide interface engineering. For LaCoO 3−x materials, it is undoubtedly critical to understand the structure variations of thin films caused by different interface conditions for the successful application of thin films in electronic devices such as solid oxide fuel cells, oxygen separation membranes, gas sensors, rechargeable batteries, memristors, etc. Oxygen vacancy configurations and concentration are coupled with the magnetic, electronic, and transport properties of perovskite oxides, and manipulating the physical properties by tuning the vacancy structures of thin films is crucial for applications of these functional devices. Here, we report a direct atomic-scale observation of the variation of the oxygen vacancy structure in strained LaCoO 3−x films under different boundary conditions. Using aberrationcorrected transmission electron microscopy, we observe that in an 8 nm LaCoO 3−x film grown on the SrTiO 3 substrate, the ordered oxygen vacancies stack layer by layer along the in-plane direction with a period of 3 unit cells (UCs) and appear in a staggered-arrangement way. When a 20 nm BiFeO 3 film is grown on top of the LaCoO 3−x film, the oxygen vacancy concentration in the LaCoO 3−x film reduces and becomes very low. Different from that in free upper surfaces, the oxygen vacancy concentration is too low to be ordered. When a 20 nm PbTiO 3 film is grown on the LaCoO 3−x film, the oxygen vacancy concentration in the LaCoO 3−x film is very high, and different from that of the free upper surface, the ordered oxygen vacancies stack layer by layer along the out-of-plane direction with a period of 2 UCs, and the oxygen vacancies stack in a nonstaggered-arrangement way. Further reducing the film thickness, when a 6 UC PbTiO 3 film is grown on the 8 UC LaCoO 3−x film, the oxygen vacancy concentration in the LaCoO 3−x film is lower than that of 20 nm PTO/8 nm LCO/STO, and the ordered oxygen vacancies still stack layered along the out-of-plane direction with a period of 2 UCs, but the oxygen vacancies stack in a staggered-arrangement way. First-principles calculations decipher the atomic-scale mechanism of oxygen vacancy distribution. These results suggest that oxygen vacancy distribution is heavily associated with interface configurations. These studies are of great significance for understanding the behavior of oxygen vacancy and guiding the design of different interfaces to achieve the appropriate structure and performance for functional electronic devices.

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“…Ferromagnetic-Insulators (FM-Is) are opening new avenues for next generation spintronic devices and spin wave information processing applications [1,2,3,4,5,6]. The exchange field proximity effect from FM state and negligible effective charge current due to I state, make FM-I useful as spin filter [7], quantum topological system [8], and dissipationless medium [9].…”

Section: Introductionmentioning

confidence: 99%

“…The exchange field proximity effect from FM state and negligible effective charge current due to I state, make FM-I useful as spin filter [7], quantum topological system [8], and dissipationless medium [9]. Achieving control over the ground state in FM-Is can further extend the feasibility of these systems in aforementioned technological perspectives [3].…”

Section: Introductionmentioning

confidence: 99%

Robust electronic and tunable magnetic states in Sm$ _{2} $NiMnO$ _{6} $ ferromagnetic insulator

Majumder,

Tripathi,

Píš

et al. 2022

Preprint

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Ferromagnetic insulators (FM-Is) are the materials of interest for new generation quantum electronic applications. Here, we have investigated the physical observables depicting FM-I ground states in epitaxial Sm 2 NiMnO 6 (SNMO) double perovskite thin films fabricated under different conditions to realize different level of Ni/Mn anti-site disorders (ASDs). The presence of ASDs immensely influence the characteristic magnetic and anisotropy behaviors in SNMO system by introducing short scale antiferromagnetic interactions in predominant long range FM ordered host matrix. Charge disproportion between cation sites in form of N i 2+ + M n 4+ −→ N i 3+ + M n 3+ , causes mixed valency in both Ni and Mn species, which is found insensitive to ASD concentrations. Temperature dependent photo emission, photo absorption measurements duly combined with cluster model configuration interaction simulations, suggest that the eigenstates of Ni and Mn cations can be satisfactorily described as a linear combination of the unscreened d n and screened d n+1 L (L: O 2p hole) states. The electronic structure across the Fermi level (E F ) exhibits closely spaced Ni 3d, Mn 3d and O 2p states. From occupied and unoccupied bands, estimated values of the Coulomb repulsion energy (U ) and ligand to metal charge transfer energy (∆), indicate charge transfer insulating nature, where remarkable modification in Ni/Mn 3d -O 2p hybridization takes place across the FM transition temperature. Existence of ASD broadens the Ni, Mn 3d spectral features, whereas spectral positions are found to be unaltered. Hereby, present work demonstrates SNMO thin film as a FM-I system, where FM state can be tuned by manipulating ASD in the crystal structure, while I state remains intact.

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(LaCoO3)n/(SrCoO2.5)

Cited by 10 publications

References 31 publications

Thickness Dependence of Oxygen Vacancy Ordering in Strained LaCoO_3–x Thin Films

Thickness Dependence of Oxygen Vacancy Ordering in Strained LaCoO_3–x Thin Films

Interface Engineering of Oxygen Vacancy Ordering in an Oxide Superlattice

Robust electronic and tunable magnetic states in Sm$ _{2} $NiMnO$ _{6} $ ferromagnetic insulator

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(LaCoO3)n/(SrCoO2.5)

Cited by 10 publications

References 31 publications

Thickness Dependence of Oxygen Vacancy Ordering in Strained LaCoO3–x Thin Films

Thickness Dependence of Oxygen Vacancy Ordering in Strained LaCoO3–x Thin Films

Interface Engineering of Oxygen Vacancy Ordering in an Oxide Superlattice

Robust electronic and tunable magnetic states in Sm$ _{2} $NiMnO$ _{6} $ ferromagnetic insulator

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Thickness Dependence of Oxygen Vacancy Ordering in Strained LaCoO_3–x Thin Films

Thickness Dependence of Oxygen Vacancy Ordering in Strained LaCoO_3–x Thin Films