Refinement of the structure of anatase at several temperatures*

Horn, Manfred; Schwerdtfeger, C.F.; Meagher, E. P.

doi:10.1524/zkri.1972.136.3-4.273

Cited by 379 publications

(186 citation statements)

References 11 publications

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“…The structures are rearranged from Ref. [44,45] The CW-EPR analysis of trapped electron centers (Ti 3+ ) in -rutile and brookite performed in the present work allowed us to accomplish a picture of the EPR features of such centres for all the polymorphs of titanium dioxide, whose crystal structures are reported in Scheme 1A. This analysis started with the EPR investigation of anatase [23], followed by the study on the properties of the interstitial Ti 3+ in rutile.…”

Section: Electron Trapping In Brookitementioning

confidence: 96%

Nature of Reduced States in Titanium Dioxide as Monitored by Electron Paramagnetic Resonance. II: Rutile and Brookite Cases

et al. 2014

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Abstract.We have systematically used Electron Paramagnetic Resonance (EPR) to understand the nature of excess electron centers in Titanium dioxide and to classify their spectroscopic features. Excess electrons in TiO 2 (probably the most important photoactive oxide) have been generated either by photoinduced charge separation or by reductive treatments and are stabilized in the solid by titanium ions which reduce to paramagnetic Ti 3+ . These are monitored by EPR and classified on the basis of their g tensor values in order to amend a certain confusion present in the literature about this subject. In the previous paper of this series (S. Livraghi et al. J. Phys. Chem. C 2011, 115, 25413) excess electron centers in anatase were investigated while the present one is devoted to rutile and brookite, the two other TiO 2 polymorphs, in the aim of providing a thorough and consistent guideline to researchers working in the wide area of titanium dioxide applications.2

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Section: Electron Trapping In Brookitementioning

confidence: 96%

Nature of Reduced States in Titanium Dioxide as Monitored by Electron Paramagnetic Resonance. II: Rutile and Brookite Cases

et al. 2014

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“…The c-axis length for bulk anatase is 9.515Å (Space group I41/amd). [19] On comparing the average value of 'c' for the a-TiO2/NGO films with thickness from 20nm to 100nm, it can be observed that its value changes from 9.367Å to 9.487Å for 20nm to 60nm films. However the value of 'c' decreases at 80nm to 9.484Å and is decreased further for 100nm to 9.469Å, as compared to the 60nm thick films.…”

Section: Submitted Tomentioning

confidence: 99%

“…The crystal structure of the NGO substrate is orthorhombic with lattice parameters [21] [19] The lattice mismatch between the NGO substrate and anatase is slightly different along the a and b directions, with values of 2.14% and 1.91% respectively. These values are slightly greater than the measured average a and b strains of 1.67 and 1.44% respectively for the thinnest 20nm films (see Figure 1), as would be expected, and confirm that an in-plane biaxial strain originates due to lattice mismatch between the film and the NGO substrate.…”

Section: Submitted Tomentioning

confidence: 99%

Interesting Evidence for Template‐Induced Ferroelectric Behavior in Ultra‐Thin Titanium Dioxide Films Grown on (110) Neodymium Gallium Oxide Substrates

Deepak

Miguel

Keeney

et al. 2014

Adv Funct Materials

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This paper reports the first-ever presentation of evidence for room-temperature ferroelectric behavior in anatase-phase titanium dioxide (a-TiO2). It is shown that behaviour strongly indicative of ferroelectric behavior is induced in ultra-thin (20nm to 80nm) biaxially-strained epitaxial films of a-TiO2 deposited by liquid injection chemical vapour deposition onto (110) Submitted to neodymium gallium oxide (NGO) substrates. The structural properties of the films were analyzed by x-ray diffraction and high-resolution transmission electron microscopy, which showed significant orthorhombic strain in films. Possible ferroelectric behavior was probed by piezoresponse force microscopy (PFM). The films on NGO showed a switchable dielectric spontaneous polarization, the ability to retain polarization information written into the film using the PFM tip for extended periods (several hours) and at elevated temperatures (up to 100°C) without significant loss, and the disappearance of the polarization at a temperature between 180 and 200°C, indicative of a Curie temperature within this range. This combination of effects is believed to constitute strong experimental evidence for ferroelectric behavior, which has not hitherto been reported in a-TiO2 and opens up the possibility for a range of new devices and materials applications. A model is presented for the effects of large in-plane strains on the crystal structure of anatase which provides a possible explanation for the experimental observations.

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“…The presence of anatase was confirmed by μ-XRD in samples 1, 2a and 9. At low temperature, anatase is the most common polymorph of titanium dioxide, stable in 600-900°C range, whereas above this temperature threshold anatase converts into rutile, depending on grain size, atmosphere and nature and amount of impurities [25]. Therefore, the presence of anatase may indicate a firing temperature lower than 900°C.…”

Section: Milpillas Phase (1200-1450 Ad)mentioning

confidence: 99%

The ceramics of Malpaís of Zacapu, Michoacán, Mexico, during the Early and Middle Postclassic periods (900–1450AD): Micro-chemical characterization of surface paintings

Jadot

Schiavon

Manso

2016

Spectrochimica Acta Part B: Atomic Spectroscopy

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Tarascan ceramic sherds from two Postclassical archaeological sites (900-1450 AD) at the Malpaís of Zacapu, Michoacán, Mexico, were investigated by combining Back-Scattered Scanning Electron Microscopy and Energy Dispersive Spectroscopy (BSEM-EDS), μ-X-Ray Diffractometry (μ-XRD), μ-X-ray Fluorescence Spectroscopy (μ-XRF) and μ-Raman Spectroscopy. These sherds are famous for their forms and decorations although the composition of its raw materials remains so far unknown and focused only on the composition of the ceramic paste. For the purpose of surface decoration characterization, the pigments used in slips and paintings were identified as hematite, magnetite, amorphous carbon, graphite and lignite. Furthermore chemical and molecular structure determination allowed the identification of technological aspects such as the firing temperatures and atmospheres used in ceramics production.

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Refinement of the structure of anatase at several temperatures*

Cited by 379 publications

References 11 publications

Nature of Reduced States in Titanium Dioxide as Monitored by Electron Paramagnetic Resonance. II: Rutile and Brookite Cases

Nature of Reduced States in Titanium Dioxide as Monitored by Electron Paramagnetic Resonance. II: Rutile and Brookite Cases

Interesting Evidence for Template‐Induced Ferroelectric Behavior in Ultra‐Thin Titanium Dioxide Films Grown on (110) Neodymium Gallium Oxide Substrates

The ceramics of Malpaís of Zacapu, Michoacán, Mexico, during the Early and Middle Postclassic periods (900–1450AD): Micro-chemical characterization of surface paintings

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