Original scientific paper

Transport Properties of YbCu_4.4 Giant-unit-cell Metallic Compound

Petar Popčević orcid.org/0000-0001-5442-2370 ; Laboratory for the Physics of Transport Phenomena, Institute of Physics, Bijenička c. 46, HR-10000 Zagreb, Croatia
Igor Smiljanić ; Laboratory for the Physics of Transport Phenomena, Institute of Physics, Bijenička c. 46, HR-10000 Zagreb, Croatia
Neven Barišić ; Laboratory for the Physics of Transport Phenomena, Institute of Physics, Bijenička c. 46, HR-10000 Zagreb, Croatia
Ana Smontara ; Laboratory for the Physics of Transport Phenomena, Institute of Physics, Bijenička c. 46, HR-10000 Zagreb, Croatia
Janez Dolinšek ; Jožef Stefan Institute, University of Ljubljana, Jamova 39, SI-1000 Ljubljana, Slovenia
Saskia Gottlieb-Schönmeyer ; Johann Wolfgang Goethe-Universität, Max-von-Laue-Straße 1, D-60438 Frankfurt am Main, Germany

Abstract

The experimental results of the transport properties: electrical resistivity, ρ, thermopower, S, and thermal conductivity, κ, of a polycrystalline sample of YbCu_4.4, in the temperature range 2 to 300 K, are presented. In contrast to the divalent YbCu₂ compound, YbCu_4.4 has transport properties typical of an intermediate valence compound: relatively high electrical resistivity and large thermoelectric power. The electrical resistivity ρ(T) exhibits a typical Kondo lattice systems’ behaviour, with a room temperature valueof ρ_r.t. ≈ 60 μΩ cm, while thermoelectric power S(T) is negative in the whole investigated temperature range. S(T) shows a distinct temperature dependence, which is attributed to the Kondo interaction. The room temperature, r.t., value of the thermal conductivity is κ_r.t. ≈ 20 W/mK. The pronounced maximum in κ(T) at low temperatures, which is frequently found in simple nonmagnetic and rather pure samples, is absent. The thermal conductivity decreases monotonically in a whole temperature range with a change in the slope around 50 K. The absence of a maximum in κ(T) could be related to the larger contribution of residual scattering processes and to the considerably weak coupling of electrons with phonons. The results are compared to the reported transport properties of similar Ce-Cu and Yb-Cu Kondo systems.

Keywords

complex metallic alloys; physical properties; electrical resistivity; thermopower; thermal conductivity

Hrčak ID:

52238

URI

https://hrcak.srce.hr/52238

Publication date:

30.4.2010.

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