Influence of sample preparation on the glass-like acoustic properties of pure crystalline tantalum

König, Reinhard; Mrowka, F.; Usherov-Marshak, I.; Esquinazi, P.; Wasserbäch, W.

doi:10.1016/s0921-4526(02)00565-3

Cited by 4 publications

(18 citation statements)

References 4 publications

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“…2), a magnitude of the lattice thermal conductivity at T ¼ 0.1 K is obtained which is by a factor of about 10 too high as compared with the experimental values of the thermal conductivity. In the case of highpurity tantalum, from internal friction experiments [5] a magnitude of the lattice thermal conductivity is obtained which is by a factor of about 15 too high as compared with the experimental values of the thermal conductivity [7,8]. A similar difference of a factor 10 has been observed in the case of high-purity niobium single crystals deformed at 195 K [4].…”

Section: The Interaction Of Phonons With Mobile Kinks In Dislocationsmentioning

confidence: 70%

“…Recent experimental studies of the acoustic properties of plastically deformed, highpurity polycrystalline aluminum [1][2][3], high-purity single crystals of niobium [3,4] and high-purity polycrystalline foils of tantalum [5] revealed an unexpectedly high, almost temperature independent internal friction Q À1 , with a magnitude of about 10 --4 in the superconducting state. By contrast, the internal friction Q À1 of undeformed specimens is much smaller, typically 10 --6 [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

“…By contrast, the internal friction Q À1 of undeformed specimens is much smaller, typically 10 --6 [1][2][3][4][5]. It had been speculated that the deformation leads to "glass-like" two-level tunneling systems [1,2].…”

Section: Introductionmentioning

confidence: 99%

“…The present work is part of an experimental and theoretical programme in which the nature of the interaction between phonons and dislocations has been investigated in high-purity crystalline specimens of aluminum, niobium and tantalum [1][2][3][4][5][6][7][8]. The interaction mechanisms were studied using different experimental techniques such as internal friction Q --1 [1][2][3][4][5], lattice thermal conductivity j [3,[6][7][8], specific heat c p [6,8] and heat release [6].…”

Section: Introductionmentioning

confidence: 99%

“…The interaction mechanisms were studied using different experimental techniques such as internal friction Q --1 [1][2][3][4][5], lattice thermal conductivity j [3,[6][7][8], specific heat c p [6,8] and heat release [6]. Comparison between experimental results and theoretical models requires that the defect structure of the investigated specimens be known (i.e.…”

Section: Introductionmentioning

confidence: 99%

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Low-Temperature Acoustic and Thermal Properties of Plastically Deformed, High-Purity Polycrystalline Aluminum

Wasserbäch¹,

Abens

Sahling

et al. 2001

phys. stat. sol. (b)

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The low-temperature internal friction Q --1 , thermal conductivity j, specific heat c p and heat release of plastically deformed, high-purity aluminum polycrystals have been investigated and have been compared with measurements on an amorphous SiO 2 specimen. Plastic deformation has a pronounced effect on both internal friction Q --1 and thermal conductivity j in the superconducting state. The magnitude of the internal friction Q --1 can be increased over two orders by plastic deformation over that observed on an annealed sample, and approaches a value approximately equal to that of the amorphous SiO 2 specimen. The lattice thermal conductivity j of the deformed specimens also has a magnitude which is of the same order as that of amorphous SiO 2 , it is, however, nearly independent of the amount of deformation. No "glass-like" anomalies could be observed in the specific heat c p and heat release measurements. The specific heat c p approaches a T 3 -relationship at the lowest temperatures investigated, and heat release experiments clearly show no longtime energy relaxation effects. Thus, it must be concluded that the defects introduced into deformed aluminum cannot be described with the tunneling model which had been proposed to describe the low temperature elastic and thermal properties of amorphous solids and which is based on the assumption of a constant spectral density of tunneling states. The phonon scattering mechanism observed in the deformed aluminum is tentatively related to the interaction of phonons with geometrical kinks in dislocations.

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Section: The Interaction Of Phonons With Mobile Kinks In Dislocationsmentioning

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Low-Temperature Acoustic and Thermal Properties of Plastically Deformed, High-Purity Polycrystalline Aluminum

Wasserbäch¹,

Abens

Sahling

et al. 2001

phys. stat. sol. (b)

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Low-Temperature Internal Friction in High-Purity Monocrystalline and Impure Polycrystalline Niobium after Plastic Deformation

Wasserbäch¹,

Thompson

2001

phys. stat. sol. (a)

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The internal friction Q --1 of plastically deformed, high-purity monocrystalline and impure polycrystalline niobium specimens was measured in the temperature range between 65 mK and about 2 K. Plastic deformation has a pronounced effect on the internal friction Q --1 of the high-purity monocrystalline specimens, and the effect has been found to be almost temperature independent. By contrast, surprisingly, the internal friction Q --1 of the impure polycrystalline specimens was found to be almost independent of the extent of plastic deformation. Comparison of the experimental results with different models of a dynamic scattering of acoustic phonons by dislocations leads to the conclusion that the results cannot be explained with the two-level tunneling model. Instead it is suggested that a strong interaction between acoustic phonons and geometrical kinks in nonscrew dislocations is responsible for the observed internal friction Q --1 .

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Low-temperature internal friction and thermal conductivity in plastically deformed metals due to dislocation dipoles and random stresses

2005

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The contribution to the low frequency internal friction and the thermal conductivity due to optically vibrating edge dislocation dipoles is calculated within the modified Granato-Lücke string model. The results are compared with the recent experiments on plastically deformed samples of Al, Ta and Nb at low temperatures. It is shown that the presence of a reasonable density of optically vibrating dislocation dipoles provides a good fit to the thermal conductivity in superconducting samples. At the same time, the internal friction experiments can not be described within the standard fluttering string mechanism. We found that the problem can be solved by assuming random forces acting on the dislocation dipoles. This gives an additional contribution to the internal friction which describes well the experimental data at low temperatures while their contribution to the thermal conductivity is found to be negligible.

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Influence of sample preparation on the glass-like acoustic properties of pure crystalline tantalum

Cited by 4 publications

References 4 publications

Low-Temperature Acoustic and Thermal Properties of Plastically Deformed, High-Purity Polycrystalline Aluminum

Low-Temperature Acoustic and Thermal Properties of Plastically Deformed, High-Purity Polycrystalline Aluminum

Low-Temperature Internal Friction in High-Purity Monocrystalline and Impure Polycrystalline Niobium after Plastic Deformation

Low-temperature internal friction and thermal conductivity in plastically deformed metals due to dislocation dipoles and random stresses

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