Elastic constants of rutile (TiO2)

Wachtman, J. B.; Tefft, Wayne E.; Lam, D. G.

doi:10.6028/jres.066a.047

Cited by 84 publications

(19 citation statements)

References 21 publications

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“…The Young’s modulus and Poisson’s ratio determined in Ref. 47 were used to model the strain. The computed energy difference between the sites 1 and 2 under the stress along the [100] direction is shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

Hydrogen motion in rutile TiO2

Hupfer

Monakhov

Svensson

et al. 2017

Sci Rep

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Uniaxial-stress experiments have been performed for the 3287- and 2445-cm−1 local vibrational modes assigned to the positive charge state of interstitial hydrogen and deuterium , respectively, occurring in mono-crystalline rutile TiO2. The onset of the defect alignment under the stress applied perpendicular to the [001] axis is detected at 165 K (185 K), which corresponds to the activation energy of 0.53 eV (0.58 eV) for interstitial hydrogen (deuterium). Based on these findings the diffusion constants of and along the [001] axis of TiO2 are determined. The experimental data are complemented by density-functional theory calculations and compared with the earlier results on the diffusion of / at elevated temperatures up to 700 °C. It is found that the activation energy value deduced from our low-temperature stress measurements yields a very good agreement with the high-temperature data, covering a dynamic range of 12 orders of magnitude.

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Section: Discussionmentioning

confidence: 99%

Hydrogen motion in rutile TiO2

Hupfer

Monakhov

Svensson

et al. 2017

Sci Rep

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“…Therefore, we used elastic constants of minerals with compositions that were comparable to previously published mineral chemistry for the Breaksea Orthogneiss and the Malaspina Pluton Clarke et al, 2013;Chapman et al, 2015). Consequently, we used single-crystal stiffnesses of Bhagat et al (1992) for omphacite (density =3.33 g/cm 3 ), Chai et al (1997) for garnet ( =3.81 g/cm 3 ), Collins and Brown (1998) for diopside ( =3.33 g/cm 3 ), Jackson et al (2007) for enstatite ( =3.2 g/cm 3 ), Brown et al (2006) for plagioclase ( =2.68 g/cm 3 ), Aleksandrov and Ryzhova (1962) for K-feldspar, Lakshtanov et al (2007) for quartz, Weidner and Ito (1985) for ilmenite , Wachtman Jr et al (1962) for rutile, and Sha et al (1994) for apatite. Elastic stiffness of pargasite was approximated with those of hornblende (Aleksandrov and Ryzhova, 1961).…”

Section: Calculation Of Seismic Propertiesmentioning

confidence: 99%

Seismic anisotropy from compositional banding in granulites from the deep magmatic arc of Fiordland, New Zealand

Cyprych

Piazolo

Almqvist

2017

Earth and Planetary Science Letters

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We present calculated seismic velocities and anisotropies of mafic granulites and eclogites 16 from the Cretaceous deep lower crust (~40-65 km) of Fiordland, New Zealand. Both rock 17 types show a distinct foliation defined by cm-scale compositional banding. Seismic properties 18 are estimated using the Asymptotic Expansion Homogenisation-Finite Element (AEH-FE) method that, unlike the commonly used Voigt-Reuss-Hill homogenisation, incorporates the phase boundary network into calculations. The predicted mean P-and S-wave velocities are consistent with previously published data for similar lithologies from other locations (e.g., Kohistan Arc), although we find higher than expected anisotropies (AV P ~5.0-8.0 %, AV S ~ 3.0-6.5 %) and substantial S-wave splitting along foliation planes in granulites. This seismic signature of granulites results from a density and elasticity contrast between cm-scale pyroxene ± garnet stringers and plagioclase matrix rather than from crystallographic orientations alone. Banded eclogites do not show elevated anisotropies as the contrast in density and elastic constants of garnet and pyroxene is too small. The origin of compositional banding in Fiordland granulites is primarily magmatic and structures described here are expected to be typical for the base of present day magmatic arcs. Hence, we identify a new potential source of anisotropy within this geotectonic setting.

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“…This is equivalent to the one used by Casimir. 32 The values for vi and v t \,n were derived from elastic constant data 34 giving fl a = 6.16X10 5 cm/sec. The formula £=1.21(ZiZ, 2 ) 1/2 , 35 where LiU is the cross section of the sample, was used to determine the length parameter from the physical sample size resulting in Z=2.16 mm.…”

Section: A Pure and Niobium-doped Rutilementioning

confidence: 99%

Thermal Conductivity and Thermoelectric Power of Rutile (TiO2)

Thurber

Mante

1965

Phys. Rev.

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The thermal conductivity K and the thermoelectric power Q of single-crystal samples of rutile were measured from 2 to 300 °K. Pure, niobium-doped, vacuum-reduced, and hydrogen-reduced specimens were investigated. The thermal conductivity of the pure crystals is similar to that usually found for insulators, with a maximum at about 15°K. Boundary scattering determines K below the maximum, and in the range 25 to 100°K the conductivity varies exponentially with temperature, which is characteristic of umklapp scattering. The Callaway expression for K was used to fit the data over the entire temperature range. From measurements in both the c and an a direction, it was found that the anisotropy ratio K c /K a = 1.5±0.1 above 25°K. The ratio decreases below 25°K to a limiting value of 1.05±0.1. A sample doped with 0.1% Nb has a thermal conductivity quite similar to the pure Ti02. The K of the reduced samples is quite depressed at low temperatures and a discussion of possible processes is included. On oxidation of a reduced sample it was discovered that the thermal conductivity did not recover completely to the original values measured on the same specimen before reduction. For one crystal a comparison of K in the reduced and reoxidized states yields values for the extra thermal resistance which are compatible with the number of point defects introduced by the reduction. The thermoelectric power of the semiconducting samples (Nb-doped and reduced) increases rapidly below 100°K, indicating a large phonon-drag contribution.

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Elastic constants of rutile (TiO2)

Abstract: The six clastic con stan ts (a nd s ix clasti c compli a nces) of ru t ile were d eter mi ne d in tlw kilo cycle p er second fr equ e ncy range by a l'C'so na nce m ethod . The st a nd a rd c1 t'v iat i o n~ ran ge from 0.2 p erce nt for SIl to 4. 3 perce nt for 81 3.

Cited by 84 publications

References 21 publications

Hydrogen motion in rutile TiO2

Hydrogen motion in rutile TiO2

Seismic anisotropy from compositional banding in granulites from the deep magmatic arc of Fiordland, New Zealand

Thermal Conductivity and Thermoelectric Power of Rutile (TiO2)

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