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Transport Properties of YbCu4.4 Giant-unit-cell Metallic Compound
; Laboratory for the Physics of Transport Phenomena, Institute of Physics, Bijenička c. 46, HR-10000 Zagreb, Croatia
The experimental results of the transport properties: electrical resistivity, ρ, thermopower, S, and thermal conductivity, κ, of a polycrystalline sample of YbCu4.4, in the temperature range 2 to 300 K, are presented. In contrast to the divalent YbCu2 compound, YbCu4.4 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 value of ρr.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 κr.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.
Hrčak ID: 52238
Posjeta: 548 *