engleski

Transport properties of Yb-Cu giant-unit-cell complex metallic compound

The experimental results of the transport properties: electrical resistivity (r ), thermopower (S) and thermal conductivity (K ) 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 shows typical r (T) dependence of Kondo lattice systems with a room temperature value r(300 K) ≈ 60 mikro Ohm 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 value of the thermal conductivity is K (RT) ≈ 20 W/mK. The pronounced maximum in K(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 K (T) could be related to a larger contribution of residual scattering processes and a considerable weak coupling of electrons with phonons. The results are compared to the reported transport properties of similar Ce-Cu and Yb-Cu Kondo systems.

complex metallic alloys; physical properties

Dio istraživanja prikazanih u radu je Petar Popčević kao poster "Transport properties of a YbCu4.5 complex metallic alloy compound" prezentirao na skupu "Frontiers in Complex Metallic Alloys" (cma2008.ifs.hr). Rad je objavljen u znanstvenom časopisu Croatica Chemica Acta (S.I.) posvećenom profesoru Boranu Leontiću.