Local Conduction at the BiFeO3‐CoFe2O4 Tubular Oxide Interface

Hsieh, Y. H.; Liou, Jia Ming; Huang, Bo; Chen, Liang; He, Qing; Zhan, Qian; Chiu, Ya-Ping; Chen, Yi Chun; Chu, Ying Hao

doi:10.1002/adma.201201929

Cited by 73 publications

(96 citation statements)

References 27 publications

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“…Figure 8(c) shows the mapping of the calculated area of the hysteretic current-voltage curves at each spatial point. 44,45 As the color changes from blue to red, the ionic effects are stronger. The red-colored area, indicating high ion conduction, mainly appears at the vertical heterointerfaces and is consistent with the electrically conducting area measured by conducting AFM.…”

Section: A Oxygen Deficiency At Vertical Heterointerfaces Due To Strmentioning

confidence: 99%

“…Very recently, as shown in Figure 1(d), new and novel device architectures, vertically aligned nanostructured (VAN) films, [43][44][45][46][47][48][49][50][51][52][53] were developed to overcome several issues in conventional ionic devices as mentioned above. Basically, the development of ionic devices by using VAN films started from a similar motivation of laterally aligned heteroepitaxy films.…”

Section: New Device Architectures For Ionic Devicesmentioning

confidence: 99%

“…Using TEM, a similar structural incompatibility was also observed at the vertical heterointerfaces in BiFeO 3 -CoFe 2 O 4 VAN films. 44 This interface was further investigated by cross-sectional scanning tunneling microscopy and spectroscopy, as shown in Figure 10. The bandgap was found to shrink across the BiFeO 3 /CoFe 2 O 4 interfaces.…”

Section: A Oxygen Deficiency At Vertical Heterointerfaces Due To Strmentioning

confidence: 99%

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Research Update: Fast and tunable nanoionics in vertically aligned nanostructured films

Lee

MacManus‐Driscoll

2017

APL Materials

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This review provides the design principles to develop new nanoionic applications using vertically aligned nanostructured (VAN) thin films, incorporating two phases which self-assemble in one film. Tunable nanoionics has attracted great attention for energy and device applications, such as ion batteries, solid oxide fuel cells, catalysts, memories, and neuromorphic devices. Among many proposed device architectures, VAN films have strong potential for nanoionic applications since they show enhanced ionic conductivity and tunability. Here, we will review the recent progress on state-of-the-art nanoionic applications, which have been realized by using VAN films. In many VAN systems made by the inclusion of an oxygen ionic insulator, it is found that ions flow through the vertical heterointerfaces. The observation is consistent with structural incompatibility at the vertical heteroepitaxial interfaces resulting in oxygen deficiency in one of the phases and hence to oxygen ion conducting pathways. In other VAN systems where one of the phases is an ionic conductor, ions flow much faster within the ionic conducting phase than within the corresponding plain film. The improved ionic conduction coincides with much improved crystallinity in the ionically conducting nanocolumnar phase, induced by use of the VAN structure. Furthermore, for both cases Joule heating effects induced by localized ionic current flow also play a role for enhanced ionic conductivity. Nanocolumn stoichiometry and strain are other important parameters for tuning ionic conductivity in VAN films. Finally, double-layered VAN film architectures are discussed from the perspective of stabilizing VAN structures which would be less stable and hence less perfect when grown on standard substrates.

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Section: A Oxygen Deficiency At Vertical Heterointerfaces Due To Strmentioning

confidence: 99%

Section: New Device Architectures For Ionic Devicesmentioning

confidence: 99%

Section: A Oxygen Deficiency At Vertical Heterointerfaces Due To Strmentioning

confidence: 99%

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Research Update: Fast and tunable nanoionics in vertically aligned nanostructured films

Lee

MacManus‐Driscoll

2017

APL Materials

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“…Similarly, magnetoelectric coupling can emerge at the interfaces. [375][376][377] Finally, in the last several years progressively more attention has been paid to the coupling between physical and electrochemical phenomena in oxides, especially pronounced in nanoscale systems 278,279,[378][379][380][381] Similarly to the magnetoelectricity and electronic transport, the coupling between ferroelectric functionality and (electro)chemistry can be bulk and interface driven. In the bulk, Morozovska 382 analyzed the case of Vegard strain changing the sign of the first term in the Landau expansion, resulting in a ferroelectric phase transition.…”

Section: Phenomenamentioning

confidence: 99%

Ferroelectric or non-ferroelectric: Why so many materials exhibit “ferroelectricity” on the nanoscale

Vasudevan

Balke

Maksymovych

et al. 2017

Applied Physics Reviews

270

206

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Ferroelectric materials have remained one of the foci of condensed matter physics and materials science for over 50 years. In the last 20 years, the development of voltage-modulated scanning probe microscopy techniques, exemplified by Piezoresponse force microscopy (PFM) and associated time-and voltage spectroscopies, opened a pathway to explore these materials on a single-digit nanometer level. Consequently, domain structures, walls and polarization dynamics can now be imaged in real space. More generally, PFM has allowed studying electromechanical coupling in a broad variety of materials ranging from ionics to biological systems. It can also be anticipated that the recent Nobel prize 1 in molecular electromechanical machines will result in rapid growth in interest in PFM as a method to probe their behavior on single device and device assembly levels. However, the broad introduction of PFM also resulted in a growing number of reports on nearly-ubiquitous presence of ferroelectric-like phenomena including remnant polar states and electromechanical hysteresis loops in materials which are non-ferroelectric in the bulk, or in cases where size effects are expected to suppress ferroelectricity. While in certain cases plausible physical mechanisms can be suggested, there is remarkable similarity in observed behaviors, irrespective of the materials system. In this review, we summarize the basic principles of PFM, briefly discuss the features of ferroelectric surfaces salient to PFM imaging and spectroscopy, and summarize existing reports on ferroelectric-like responses in non-classical ferroelectric materials. We further discuss possible mechanisms behind observed behaviors, and possible experimental strategies for their identification.3

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“…layered) heterostructures [10]. It should be pointed out that, despite the vertical nanopillar structure being less clamped to the matrix, conductive interfaces can form and, thus, can electrically shut down the application [11]. As a result, much attention is focused on the layered heterostructures where another problem is highlighted.…”

Section: Introductionmentioning

confidence: 99%

On stoichiometry and intermixing at the spinel/perovskite interface in CoFe₂O₄/BaTiO₃ thin films

et al. 2015

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The performance of complex oxide heterostructures depends primarily on the interfacial coupling of the two component structures. This interface character inherently varies with the synthesis method and conditions used since even small composition variations can alter the electronic, ferroelectric, or magnetic functional properties of the system. The focus of this article is placed on the interface character of a pulsed laser deposited CoFe2O4/BaTiO3 thin film. Using a range of state-of-the-art transmission electron microscopy methodologies, the roles of substrate morphology, interface stoichiometry, and cation intermixing are determined on the atomic level. The results reveal a surprisingly uneven BaTiO3 substrate surface formed after the film deposition and Fe atom incorporation in the top few monolayers inside the unit cell of the BaTiO3 crystal. Towards the CoFe2O4 side, a disordered region extending several nanometers from the interface was revealed and both Ba and Ti from the substrate were found to diffuse into the spinel layer. The analysis also shows that within this somehow incompatible composite interface, a different phase is formed corresponding to the compound Ba2Fe3Ti5O15, which belongs to the ilmenite crystal structure of FeTiO3 type. The results suggest a chemical activity between these two oxides, which could lead to the synthesis of complex engineered interfaces.

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Local Conduction at the BiFeO₃‐CoFe₂O₄ Tubular Oxide Interface

Cited by 73 publications

References 27 publications

Research Update: Fast and tunable nanoionics in vertically aligned nanostructured films

Research Update: Fast and tunable nanoionics in vertically aligned nanostructured films

Ferroelectric or non-ferroelectric: Why so many materials exhibit “ferroelectricity” on the nanoscale

On stoichiometry and intermixing at the spinel/perovskite interface in CoFe₂O₄/BaTiO₃ thin films

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Local Conduction at the BiFeO3‐CoFe2O4 Tubular Oxide Interface

Cited by 73 publications

References 27 publications

Research Update: Fast and tunable nanoionics in vertically aligned nanostructured films

Research Update: Fast and tunable nanoionics in vertically aligned nanostructured films

Ferroelectric or non-ferroelectric: Why so many materials exhibit “ferroelectricity” on the nanoscale

On stoichiometry and intermixing at the spinel/perovskite interface in CoFe2O4/BaTiO3 thin films

Contact Info

Product

Resources

About

Local Conduction at the BiFeO₃‐CoFe₂O₄ Tubular Oxide Interface

On stoichiometry and intermixing at the spinel/perovskite interface in CoFe₂O₄/BaTiO₃ thin films