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Low‐Temperature Acoustic and Thermal Properties of Plastically Deformed, High‐Purity Polycrystalline Aluminum
Author(s) -
Wasserbäch W.,
Abens S.,
Sahling S.,
Pohl R.O.,
Thompson Eunjoo
Publication year - 2001
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200112)228:3<799::aid-pssb799>3.0.co;2-5
Subject(s) - materials science , amorphous solid , thermal conductivity , condensed matter physics , crystallite , phonon , aluminium , composite material , internal friction , deformation (meteorology) , quantum tunnelling , relaxation (psychology) , phonon scattering , thermal , thermodynamics , metallurgy , crystallography , chemistry , psychology , social psychology , physics , optoelectronics
The low‐temperature internal friction Q —1 , thermal conductivity κ, 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 κ 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 κ 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 long‐time 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.