Hydrogen relaxation in lutetium

Vajda, P.; Daou, J. N.; Moser, P.

doi:10.1051/jphys:01983004404054300

Cited by 29 publications

(14 citation statements)

References 37 publications

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“…A similar value for the activation energy was obtained from resistancerelaxation measurements after quenching or low-temperature electron irradiation reported to be 1 s-l a t the two respective temperatures above [7]. This means that, for both isotopes, not only the activation energy but also the absolute value of the internal friction frequency exhibits (within experimental accuracy) good agreement with the frequency v as determined from our present measurements.…”

Section: Compaiison With Pvevious Studiessupporting

confidence: 90%

“…Such an ordering process can cause an elastic relaxation if the strain fields of the H atoms involved superpose non-linearly (similarly as in a Zener relaxation). It should, however, also be noted that a pair-formation (or dissolution) process is, a t least, difficult t o understand in view of the essentially linear H-concentration dependence of the relaxation amplitude which is reported by the authors of [7].…”

Section: Compaiison With Pvevious Studiesmentioning

confidence: 97%

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Diffusion of H and D in Lutetium

Völkl

Wipf

Beaudry

et al. 1987

Physica Status Solidi (b)

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Dedicated to Prof. Dr. A. SEEGER on the occasion of his 60th birthday The anisotropy and isotope dependence of H (and D) diffusion in h.c.p. LuH,.,, and LuD,,,, is investigated in Gorsky-effect measurements (380 K < T < 540 K). In spite of the hexagonal lattice structure, no anisotropy in the diffusion behavior can be established within experimental accuracy. The nearly isotropic diffusion can be understood from a consideration of possible atomistic jump processes. The present results are compared with previous studies on H(D) diffusion in h.c.p. metals. Mittels Gorskyeffekt-Messungen wird die Anisotropie und die Isotopieabhangigkeit der Wasserstoffdiffusion in hexagonalem Lu&,,, und LuD,,,, untersucht (380 K < T < 540 K). Trotz der hexagonalen Kristallstruktur wird innerhalb der experimentellen Fehler keine Anisotropie im Diffusionsverhalten festgestellt. Das anniihernd isotrope Diffusionsverhalten kann im Rahmen eines atomistischen Sprungmodells verstanden werden. Die vorliegenden Ergebnisse werden mit friiheren Untersuchungen iiber die Diffusion von H(D) in hexagonalen Metallen verglichen. l) D-8046 Garching, FRG. ') D-6100 Darmstadt, FRG. 3, Ames, Iowa 50011, USA.

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Section: Compaiison With Pvevious Studiessupporting

confidence: 90%

Section: Compaiison With Pvevious Studiesmentioning

confidence: 97%

Diffusion of H and D in Lutetium

Völkl

Wipf

Beaudry

et al. 1987

Physica Status Solidi (b)

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“…We point out i) that although the background increased with increasing frequency, the magnitude of the relaxation peaks did not, and ii) that the Q −1 max values obtained in a previous vibrating-reed study [11] on hcp YH x polycrystals fall between the present data for the c-axis and b -axis crystals. Figure 3 shows an essentially linear relationship between Q −1 max and H concentration, which agrees with previous results for hcp YH x [10], [11] and the related system LuH x [15], and only apparently contradicts a Zener relaxation of H pairs if their binding enthalpy is considered [1], [14]. The new aspect of the data in fig.…”

supporting

confidence: 89%

A mechanical-spectroscopy study of the anelastic relaxation of hydrogen pairs in hexagonal YH _x single crystals

et al. 1996

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We have performed a mechanical-spectroscopy study on hcp YHx single crystals (x ≤ 0.1, vibrating-reed technique, 280 to 1750 Hz). In agreement with previous data from polycrystalline YHx, we find an anelastic relaxation peak at ∼ 280 K. Our single crystals show a large anisotropy in the relaxation strength which demonstrates that this peak results from a Zener relaxation of hydrogen (H) pairs. Two types of H jumps determine the relaxation kinetics. Comparison with previous QNS data identifies the jumps that cause the relaxation, showing further that their jump rates follow, over ten orders of magnitude, an Arrhenius law with an activation energy of (0.60 ± 0.03) eV.

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“…A frequency-and temperature-dependent structure is found near these temperatures in internal friction studies. 42 Relatively large systematic differences on warming and cooling ͑and hysteresis͒ were described above for the a-axis crystals above T tr . The c-axis LuD 0.005 data in Figs.…”

Section: Samplementioning

confidence: 85%

Linear thermal expansivity andCpmeasurements forLuHx
Ca
¹

1996
Phys. Rev. B
4
0
1
0
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Linear thermal expansivity ͑␣͒ measurements from 1 to 300 K and heat capacity (C p ) measurements from 1 to 110 K are reported for single crystals of the ␣-Lu hexagonal alloys LuH x and LuD x ͑xϭ0.005 and 0.053͒. The C p data confirm and extend to 110 K earlier 1 to 20 K measurements on LuH x alloys, and, in addition, show that isotope effects, if any, are small. The small x dependences of the C p 's above 8 K can be associated with small increases in the Debye temperature ⌰ 0 . This latter interpretation, which is consistent with ultrasonic and other results for these alloys, is valid only if C p is expressed as mJ/g mol K ͑essentially, per mole of Lu ions͒. The present results are in agreement with the previous conclusion from more extensive polycrystalline LuH x data that the shape of the low-temperature C p vs T relation for xр0.015 is qualitatively different from that for xу0.032. The linear thermal expansivities of the c-axis alloys, even for xϭ0.005, are significantly smaller ͑by from 3% to 20%͒ than those for the pure crystals, with large isotope effects and a large, nonlinear x dependence for the low-temperature expansivity data. Other types of data have shown a feature near 170 K which is associated with the completion of pairing of the hydrogens along the c axis in next-nearest-neighbor tetrahedral sites. A distinct ͑approximately 15 K wide͒ change in ␣ which is observed near this temperature for each alloy, except for a-axis LuD 0.005 , provides the most direct evidence of such a transition. The temperature of the c-axis discontinuity is slightly isotope and x dependent, and scales approximately with x ͓ϩ24% on warming for LuH͑or D͒ 0.053 ͔. The LuH 0.053 a-axis ␣'s show a transition at the same temperature but of opposite sign ͑Ϫ15% on warming͒. A large relative decrease in the expansivities of each of the alloys between Tϭ0 and the transition can be ascribed to a more rapid disappearance of the spin-fluctuation and electron-phonon enhancement terms for the alloys than for the pure metal. The large differences in the isotope and x dependences of the ␣ vs T relations support the postulate that the state of these alloys is quite different for xр0.015 and xу0.032.

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Hydrogen relaxation in lutetium

Cited by 29 publications

References 37 publications

Diffusion of H and D in Lutetium

Diffusion of H and D in Lutetium

A mechanical-spectroscopy study of the anelastic relaxation of hydrogen pairs in hexagonal YH _x single crystals

Linear thermal expansivity andCpmeasurements forLuHx
Ca
¹

1996
Phys. Rev. B
4
0
1
0
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Hydrogen relaxation in lutetium

Cited by 29 publications

References 37 publications

Diffusion of H and D in Lutetium

Diffusion of H and D in Lutetium

A mechanical-spectroscopy study of the anelastic relaxation of hydrogen pairs in hexagonal YH x single crystals

Linear thermal expansivity andCpmeasurements forLuHxCa1 1996Phys. Rev. B4010View full textAdd to dashboardCite

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A mechanical-spectroscopy study of the anelastic relaxation of hydrogen pairs in hexagonal YH _x single crystals

Linear thermal expansivity andCpmeasurements forLuHx
Ca
¹

1996
Phys. Rev. B
4
0
1
0
View full text Add to dashboard Cite