A study of oxygen self-diffusion in the C-direction of rutile using a nuclear technique

Derry, D.J.; Lees, D. G.; Calvert, J.M.

doi:10.1016/0022-3697(81)90011-1

Cited by 56 publications

(28 citation statements)

References 8 publications

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“…Typical activation energies associated with oxygen vacancy diffusion in TiO 2 are of the order 2.6 eV. [51][52][53][54] Even considering the effect of hole trapping which can reduce the activation energy to oxygen vacancy generation, these results suggest that diffusion of pre-existing oxygen vacancies is always much more facile than defect generation in bulk TiO 2 . However, activation energies near the electrode interface [70][71][72] or at grain boundaries 12,73,74 may be considerably lower.…”

Section: Discussionmentioning

confidence: 88%

Relevance of non-equilibrium defect generation processes to resistive switching in TiO2

Abdelouahed

McKenna

2015

Journal of Applied Physics

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First principles calculations are employed to identify atomistic pathways for the generation of vacancy-interstitial pair defects in TiO2. We find that the formation of both oxygen and titanium defects induces a net dipole moment indicating that their formation can be assisted by an electric field. We also show that the activation barrier to formation of an oxygen vacancy defect can be reduced by trapping of holes which may be injected by the electrode. The calculated activation energies suggest that generation of titanium defects is more favorable than generation oxygen defects although activation energies in both cases are relatively high (>3.3 eV). These results provide much needed insight into an issue that has been widely debated but for which little definitive experimental information is available.

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Section: Discussionmentioning

confidence: 88%

Relevance of non-equilibrium defect generation processes to resistive switching in TiO2

Abdelouahed

McKenna

2015

Journal of Applied Physics

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“…Both sources provide a reservoir of diusant (Pb) to be placed in contact with the sample surface. Powdered or ground materials have been employed as sources of diusant in many of our studies (e.g., Watson 1992, 1994;Cherniak et al 1997a, b;, and have yielded diusivities comparable to those obtained through techniques introducing diusants through other means (e.g., Derry et al 1981;Watson et al 1985;Watson 1992, 1994;Cherniak and Ryerson 1993;Giletti and Casserly 1994;Moore et al 1998). The numerous point contacts of the source powders provide essentially continuous surface coverage given the experimental geometry and the relative rapidity of grain boundary and surface diusion (e.g., Tannhauser 1956;Gjostein 1973).…”

Section: Methodsmentioning

confidence: 91%

“…Sources for data: Co, Fe, Cr, Mn, Sc, Zr(Sasaki et al 1985); Ba(Nakayama and Sasaki 1963).b Self-diusion of O and Ti. Sources for data: Ti (Akse and Whitehurst 1978); O (`wet'): M (Moore et al 1998); DF (Dennis and Freer 1993); O(`dry'): M (Moore et al 1998); D(Derry et al 1981) …”

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confidence: 99%

Pb diffusion in rutile

Cherniak¹

2000

Contrib Mineral Petrol

290

132

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Diusion of Pb was measured in natural and synthetic rutile under dry, 1 atmosphere conditions, using mixtures of Pb titanate or Pb sul®de and TiO 2 as the sources of diusant. Pb depth pro®les were then measured with Rutherford Backscattering Spectrometry (RBS). Over the temperature range 700±1100°C, the following Arrhenius relation was obtained for the synthetic rutile: D 3.9´10 )10 exp()250 12 kJ mol )1 / RT) m 2 s )1 . Results for diusion in natural and synthetic rutile were quite similar, despite signi®cant dierences in trace element compositions. Mean closure temperatures calculated from the diusion parameters are around 600°C for rutile grains of $100 lm size. This is about 100°C higher than rutile closure temperature determinations from past ®eld-based studies, suggesting that rutile is more resistant to Pb loss through volume diffusion than previously thought.

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“…The source constituents were mixed, placed in a covered Pt crucible, and heated in air overnight at 1250°C, then reground. Powdered or ground materials have been employed as sources of diffusant in numerous studies (e.g., Watson, 1992, 1994;Cherniak et al, 1997a,b;Watson and Cherniak, 1997) and have yielded diffusivities comparable to those obtained through techniques introducing diffusants by other means (e.g., Derry et al, 1981;Watson et al, 1985;Watson, 1992, 1994;Cherniak and Ryerson, 1993;Giletti and Casserly, 1994;Moore et al, 1998;Hammouda and Cherniak, 2000). The numerous point contacts of the source powders (and the sink materials described in later sections) provide essentially continuous surface coverage given the experimental geometry and the relative rapidity of grain boundary and surface diffusion (e.g., Tannhauser, 1956;Gjostein, 1973).…”

Section: Monazite Synthesis Source and Sample Preparationmentioning

confidence: 95%