Thermal conductivity and specific heat of amorphous Zr0.67Ni0.33 after structural relaxation |
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Authors: | H W Gronert D M Herlach A Schröder R van den Berg H von Löhneysen |
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Institution: | (1) Labor für Tieftemperaturphysik, Universität-Gesamthochschule Duisburg, D-4100 Duisburg, Federal Republic of Germany;(2) Institut für Raumsimulation der DFVLR, D-5000 Köln, Federal Republic of Germany;(3) 2. Physikalisches Institut der RWTH Aachen, Templergraben 55, D-5100 Aachen, Federal Republic of Germany |
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Abstract: | Low-temperature measurements of the thermal conductivity (0.3KT5K) and of the specific heatC (0.07KT3.5K) of splat-cooled amorphous superconducting Zr0.67Ni0.33(T
c
2.7K) after different annealing stages are reported. increases progressively (up to 55%) after annealing. An analysis of with the help of normal-state measurements belowT
c
in an overcritical field shows that the phonon-electron scattering remains unaltered after annealing. Hence the increase in must be entirely attributed to structure-induced (intrinsic) scattering, i.e. by two-level tunneling states (TLS) at low temperatures (T1K). The specific heat shows a small decrease aboveT
c
(by 8%) which is attributed to a small diminution of the electronic density of states at the Fermi level and to a small increase in the Debye temperature. ForTT
c
where TLS dominate, the specific heatC decreases less upon annealing than expected from the increase of in the standard tunneling model. This points to a change in the TLS relaxation time spectrum upon annealing, as observed previously for Zr
x
Cu1–x
glasses. |
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Keywords: | |
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