Diffusion of Oxygen Vacancies in Reduced Rutile (TiO<sub>2</sub>)

Iguchi, E.; Yajima, Kazuo

doi:10.1143/jpsj.32.1415

Cited by 71 publications

(41 citation statements)

References 21 publications

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“…The equilibration kinetic data may then be used for the determination of the chemical diffusion coefficient using a Fig. 1 The chemical diffusion coefficient for T i O 2 reported in the literature [9][10][11][12][13][14][15][16][17] solution of the diffusion equation, which is adequate to the specific initial and boundary conditions of the experiment.…”

Section: Definition Of Termsmentioning

confidence: 99%

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Chemical diffusion in metal oxides. Example of TiO2

Nowotny

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Nowotny

et al. 2006

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Section: Definition Of Termsmentioning

confidence: 99%

“…1, exhibit a substantial discrepancy in their absolute values and the temperature dependence [9][10][11][12][13][14][15][16]. These data will be considered below in terms of the possible impact of the applied experimental conditions on the physical meaning of the diffusion data.…”

Section: Introductionmentioning

confidence: 99%

Chemical diffusion in metal oxides. Example of TiO2

Nowotny

Бак

Nowotny

et al. 2006

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“…And although our calculated Schottky energy is evidently too low, the difference between calculated Schottky and Frenkel energies is nevertheless large and outside the probable range of uncertainty in our calculations. We predict therefore that in slightly reduced rutile, Ti0,-,, oxygen vacancies will be present, as suggested by Iguchi and Ya.jima [19], but that interstitials as proposed in a number of studies (see e. g. Kofstad [20]) will be unimportant. The problem of the defect structure of Ti0,-, is complicated by the nucleation of extended defects (see e. g. Bursill and Hyde [21]) at all but very low values of x.…”

Section: Defect Interaction Energy (Ev)mentioning

confidence: 65%

The Defect Structure of Compounds With the Rutile Structure

Catlow

James

Norgett³

1976

J. Phys. Colloques

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R6sum6. -Nous prtsentons une etude thkorique sur les propriktks de defauts dans trois composks, MnFz, MgFz et TiOz. Nos rksultats sont en contraste avec la structure de defauts connue pour les fluorites. Nous trouvons que les dksordres du type Schottky sont intrindques dans tous les trois composks, avec le transport des ions dQ a la mobilitk des lacunes dans le cas pur ou dop6. Les ktudes antkrieures sur les rutiles d'oxyde et de fluoride avaient plutBt suggerk des desordres du type interstitiel. Nous montrons cependant que notre proposition sur la structure de defaut est compatible avec les recents rksultats de Park et Nowick [2] sur la conductivitk dans MgFz et MnF2. Nous presentons ensuite une etude dktaillee sur la migration des lacunes qui montre, pour les deux types de lacunes, que le mkcanisme dominant conduit A une conductivite largement isotropique.Ce r&uItat est en accord avec I'expkrience faite sur les cristaux dopes d'ions trivalents. Avec des cristaux dopks d'ions mono-valents on a observk une forte anisotropie, ce qui est peut-&tre dQ a la mobilitk des ions dopts.Abstract. -We present a theoretical study of the defect properties of three compounds, MnF2, MgFz and TiOz. Our results predict a defect structure which is in marked contrast to that characteristic of fluorite compounds. We propose that Schottky disorder is intrinsic to all three crystals, with ion transport effected by vacancy mobility in both pure and doped materials. Earlier studies on both fluoride and oxide rutiles have, however, suggested interstitial disorder. Nevertheless, we show that our proposals are compatible with the recent data of Park and Nowick [2] on the conductivity of MgFz and MnFz. We then report a detailed study of vacancy migration and we find that, for both anion and cation vacancies, the dominant mechanism is one which will result in largely isotropic conductivity. This accords with the experimental data on crystals doped with trivalent ions ; but for monovalent doped crystals, high anisotropy has been observed, which may, however, be due to dopant mobility.

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“…It is very interesting to note that the activation energy along the a-axis, 2.42eV, is very close to the activation energy of oxygen ions 2.6eV, which diffuse by the vacancy mechanism in rutile (17). For the research of point defects in reduced rutile, it also needs to investigate the behaviour along the c-axis,.which are now in progress at our laboratory (18).…”

Section: Comparison Of Specific Resistivitiesmentioning

confidence: 77%

Influence of Contamination on Diffusion of Point Defects in Rutile Reduced in Vacuum

Iguchi

Yajima

1972

Trans. JIM

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Single crystals of rutile in the form of slices were reduced in vacuum to investigate the diffusion of point defects. The reduction was performed in three kinds of vacuum atmospheres by using (A) a diffusion pump without traps, (B) a diffusion pump with liquid nitrogen traps and (C) an ion pump. The process of reduction is considered to represent the process of diffusion of point defects induced by reduction. The diffusion coefficients of point defects in the reduced ruffle were determined by a theory of diffusion in a plane sheet with an equal surface concentration and a uniform initial distribution of solute in a sheet. These coefficients obtained in vacuum by a diffusion pump varied with the reduction time and this tendency was more remarkable in the case of (A). But the diffusion coefficients obtained in the case of (C) were nearly constant at any reduction temperature independent of the reduction time except for the beginning stage. It appears that the differences are due to the contamination introduced by the diffusion pump. By using the ion pump, the diffusion coefficient of point defects in the reduced rutile can be expressed as This activation energy is very close in value to that of oxygen ions which diffuse in rutile by the vacancy mechanism.

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Diffusion of Oxygen Vacancies in Reduced Rutile (TiO₂)

Cited by 71 publications

References 21 publications

Chemical diffusion in metal oxides. Example of TiO2

Chemical diffusion in metal oxides. Example of TiO2

The Defect Structure of Compounds With the Rutile Structure

Influence of Contamination on Diffusion of Point Defects in Rutile Reduced in Vacuum

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Diffusion of Oxygen Vacancies in Reduced Rutile (TiO2)

Cited by 71 publications

References 21 publications

Chemical diffusion in metal oxides. Example of TiO2

Chemical diffusion in metal oxides. Example of TiO2

The Defect Structure of Compounds With the Rutile Structure

Influence of Contamination on Diffusion of Point Defects in Rutile Reduced in Vacuum

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Product

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About

Diffusion of Oxygen Vacancies in Reduced Rutile (TiO₂)