Thermogravimetric and electrical study of non-stoichiometric titanium dioxide TiO2−x, between 800 and 1100°C

Marucco, J.F.; Gautron, Jean-Claude; Lemasson, Philippe

doi:10.1016/0022-3697(81)90043-3

Cited by 152 publications

(98 citation statements)

References 18 publications

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“…Among others, these studies include thermogravimetry 44,45 and electrical conductivity measurements. 14,45,46 Although the types of major defects in rutile are still under discussion, the studies generally conclude that TiO 2−x is oxygen deficient and that the predominant atomic point defects are interstitial titanium ions and/or oxygen vacancies.…”

Section: A Point Defectsmentioning

confidence: 99%

Thermodynamics of oxygen defective Magnéli phases in rutile: A first-principles study

2008

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Ab initio thermodynamics has been used to calculate the formation energies, in different environmental conditions, for a number of oxygen-defective structures in rutile. In addition to the Ti n O 2n−1 ͑3 ഛ n ഛ 5͒ Magnéli phases, the two fundamental points defects, Ti interstitials and neutral oxygen vacancies, were also considered. The predicted phase stability is compared to available experimental data and there is reasonable agreement between the calculated phase boundaries and those observed. These results are used to discuss a mechanism that has been proposed as an explanation for the formation of the crystallographic shear planes in rutile.

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Section: A Point Defectsmentioning

confidence: 99%

Thermodynamics of oxygen defective Magnéli phases in rutile: A first-principles study

2008

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“…Ion mobility at a first approximation is taken to be small enough for this assumption to be valid. Electron mobility is taken as 10 .5 m2/Vsec, according to Marucco et al [8] and hole mobility is taken as a fraction of the electron mobility.…”

Section: The Numerical Modelmentioning

confidence: 99%

P-N junctions in semiconducting TiO2 studied through computer modelling

Korfiatis

Potamianou

Thoma

1997

Ionics

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“…One aspect of the arrangement of dislocations is the dislocation-dislocation interaction and, in the oxide materials considered here, the issue of the electrostatics of dislocations and their surroundings comes into play. In the sense of Kröger-Vink defect chemistry, charged defects should interact with other charged defects because the crystal as a whole has to fulfill the electroneutrality condition demanding that the sum of all charged defects such as electrons, holes, and vacancies has to be zero in steady state [70,[76][77][78][79][80][81][82][83][84][85][86][87][88][89]. Because some of the d 0 Ti states along the dislocations in TiO 2 and SrTiO 3 are transformed into d 1 configuration, such dislocations with a surplus of d electrons cannot be electrically neutral (e.g., [31]).…”

Section: Arrangement Of Dislocationsmentioning

confidence: 99%

Influence of Dislocations in Transition Metal Oxides on Selected Physical and Chemical Properties

et al. 2018

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Studies on dislocations in prototypic binary and ternary oxides (here TiO 2 and SrTiO 3 ) using modern TEM and scanning probe microscopy (SPM) techniques, combined with classical etch pits methods, are reviewed. Our review focuses on the important role of dislocations in the insulator-to-metal transition and for redox processes, which can be preferentially induced along dislocations using chemical and electrical gradients. It is surprising that, independently of the growth techniques, the density of dislocations in the surface layers of both prototypical oxides is high (10 9 /cm 2 for epipolished surfaces and up to 10 12 /cm 2 for the rough surface). The TEM and locally-conducting atomic force microscopy (LCAFM) measurements show that the dislocations create a network with the character of a hierarchical tree. The distribution of the dislocations in the plane of the surface is, in principle, inhomogeneous, namely a strong tendency for the bundling and creation of arrays or bands in the crystallographic <100> and <110> directions can be observed. The analysis of the core of dislocations using scanning transmission electron microscopy (STEM) techniques (such as EDX with atomic resolution, electron-energy loss spectroscopy (EELS)) shows unequivocally that the core of dislocations possesses a different crystallographic structure, electronic structure and chemical composition relative to the matrix. Because the Burgers vector of dislocations is per se invariant, the network of dislocations (with additional d 1 electrons) causes an electrical short-circuit of the matrix. This behavior is confirmed by LCAFM measurements for the stoichiometric crystals, moreover a similar dominant role of dislocations in channeling of the current after thermal reduction of the crystals or during resistive switching can be observed. In our opinion, the easy transformation of the chemical composition of the surface layers of both model oxides should be associated with the high concentration of extended defects in this region. Another important insight for the analysis of the physical properties in real oxide crystals (matrix + dislocations) comes from the studies of the nucleation of dislocations via in situ STEM indentation, namely that the dislocations can be simply nucleated under mechanical stimulus and can be easily moved at room temperature.

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Thermogravimetric and electrical study of non-stoichiometric titanium dioxide TiO2−x, between 800 and 1100°C

Cited by 152 publications

References 18 publications

Thermodynamics of oxygen defective Magnéli phases in rutile: A first-principles study

Thermodynamics of oxygen defective Magnéli phases in rutile: A first-principles study

P-N junctions in semiconducting TiO2 studied through computer modelling

Influence of Dislocations in Transition Metal Oxides on Selected Physical and Chemical Properties

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