Quantification of the Ti oxidation state in BaTi1−xNbxO3 compounds

Shao, Yang; Maunders, Christian; Rossouw, David; Kolodiazhnyi, Taras; Botton, Gianluigi A.

doi:10.1016/j.ultramic.2010.05.006

Cited by 33 publications

(21 citation statements)

References 26 publications

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“…The Ti L 2 edge taken near the top interface (3 nm away from the surface) shows two main constituent peaks (t 2g and e g ) develop noticeable shoulders, as shown in the inset of Fig. 5a, in agreement with trends reported in the literature 44 . Using the Ti-L edge far from the surface (94 nm away) as a reference, we plotted the differences in Ti-L edges using a multiple least-square fitting (Fig.…”

Section: Resultssupporting

confidence: 90%

Interface-induced nonswitchable domains in ferroelectric thin films

et al. 2014

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Engineering domains in ferroelectric thin films is crucial for realizing technological applications including non-volatile data storage and solar energy harvesting. Size and shape of domains strongly depend on the electrical and mechanical boundary conditions. Here we report the origin of nonswitchable polarization under external bias that leads to energetically unfavourable head-to-head domain walls in as-grown epitaxial PbZr 0.2 Ti 0.8 O 3 thin films. By mapping electrostatic potentials and electric fields using off-axis electron holography and electron-beam-induced current with in situ electrical biasing in a transmission electron microscope, we show that electronic band bending across film/substrate interfaces locks local polarization direction and further produces unidirectional biasing fields, inducing nonswitchable domains near the interface. Presence of oxygen vacancies near the film surface, as revealed by electron-energy loss spectroscopy, stabilizes the charged domain walls. The formation of charged domain walls and nonswitchable domains reported in this study can be an origin for imprint and retention loss in ferroelectric thin films.

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Section: Resultssupporting

confidence: 90%

Interface-induced nonswitchable domains in ferroelectric thin films

et al. 2014

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“…Both spectra present very similar features, in line with the density functional theory (DFT) results that indicate comparable d orbital occupation for Ti atoms deep in the BTO and at the interface. As revealed by a recent EELS study on bulk Ti 4+ /Ti 3+ mixed-valence compounds 35 , the presence of less than 20% of Ti 3+ does not massively alter the Ti L 3,2 -edge fine structure, making a direct determination of the Ti valence difficult. However, the different energy splittings observed in the EELS spectra, namely, the 2p spin-orbit coupling giving rise to the two main L 3 and L 2 peaks, and the splitting between the non-degenerate energy levels (t 2g and e g ) for each edge, are characteristic of a primary Ti 4+ ion 35 .…”

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confidence: 99%

Interface-induced room-temperature multiferroicity in BaTiO3

et al. 2011

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Multiferroic materials possess two or more ferroic orders but have not been exploited in devices owing to the scarcity of room-temperature examples. Those that are ferromagnetic and ferroelectric have potential applications in multi-state data storage if the ferroic orders switch independently, or in electric-field controlled spintronics if the magnetoelectric coupling is strong. Future applications could also exploit toroidal moments and optical effects that arise from the simultaneous breaking of time-reversal and space-inversion symmetries. Here, we use soft X-ray resonant magnetic scattering and piezoresponse force microscopy to reveal that, at the interface with Fe or Co, ultrathin films of the archetypal ferroelectric BaTiO 3 simultaneously possess a magnetization and a polarization that are both spontaneous and hysteretic at room temperature. Ab initio calculations of realistic interface structures provide insight into the origin of the induced moments and bring support to this new approach for creating room-temperature multiferroics.

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“…[ 19 ] The position of the cross section step function was set to the maxima of the e g peak for both Ti L 3 and L 3 edges. [ 20 ] Since there is no published cross-sectional data for the Ce M 4,5 edge, only the Bremsstrahlung background profi le was subtracted. Further, the effects of plural scattering events were reduced using Fourier-ratio deconvolution [ 21 ] by zero-loss deconvolution with a reference low loss spectra.…”

Section: Methodsmentioning

confidence: 99%

Linking Interfacial Step Structure and Chemistry with Locally Enhanced Radiation‐Induced Amorphization at Oxide Heterointerfaces

Aguiar

Dholabhai

et al. 2014

Adv Materials Inter

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Nanostructured materials and their interfaces have attracted recent interest for their functionality in a wide variety of different applications. However, the origins of these properties in several instances remain unknown. One promising aspect of nanomaterials is their role in materials design for mitigating radiation damage. In particular, engineered radiation tolerant materials would exploit the presence of internal interfaces to act as recombination centers and suppress damage accumulation. Realizing this promise, however, requires a fundamental understanding of how radiation‐induced defects interact with interfaces. Thus, studying the interfacial atomic structure and chemistry before and after irradiation is critical. In this study, we have performed transmission electron microscopy on a series of pristine and ion‐irradiated oxide interfaces to probe radiation‐induced effects. The CeO2/SrTiO3 interface, chosen as a model system for these studies, is characterized by differences in SrTiO3 terminations or steps. Our salient result is that steps are centers for preferential amorphization in SrTiO3, which we attribute to defect flow across the interface induced by non‐stoichiometry in CeO2. The study concludes the interfacial atomic ordering in the form of steps thereby modifies the response to ion irradiation and suggests interface patterning as another parameter to functionalize radiation tolerant materials.

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Quantification of the Ti oxidation state in BaTi1−xNbxO3 compounds

Cited by 33 publications

References 26 publications

Interface-induced nonswitchable domains in ferroelectric thin films

Interface-induced nonswitchable domains in ferroelectric thin films

Interface-induced room-temperature multiferroicity in BaTiO3

Linking Interfacial Step Structure and Chemistry with Locally Enhanced Radiation‐Induced Amorphization at Oxide Heterointerfaces

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