In this paper we describe an experimental set-up for simultaneous measurements of thermopower and electrical resistivity at temperatures from 100 K to 1300 K. Optimal configuration of electrodes and original mechanical contacts of thermocouples, current leads and potential probes with the sample make it possible to measure a large variety of materials and result in greater flexibility with respect to the sample form and dimensions. Both bulk and thin film samples with resistances in the range from 0 up to 200 k (1 G in case of the resistivity measurement) can be investigated. Precision and high reliability of the system have been proven during more than three years of use. The resistivity and thermopower of pure Pb, Cu and Ni, and a Cr-Si thin film composite are presented as test materials to demonstrate the possibilities and accuracy of this experimental set-up.

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The electrical resistivity and thermopower S of Heusler compounds Fe 3Àx V x Al have been measured at the temperature range from 1.5 to 300 K at magnetic fields up to 15 T. The measurements of and S in the high temperature range up to 800 K have been performed. and S show a semiconducting behavior at high temperatures, and the obtained experimental energy gap increases almost linearly with increasing V concentration x. S is positive for x < 1:0 and negative for x ! 1:0 at all measured temperatures, indicating a drastic change of major carriers at x ¼ 1:0. The electron scattering due to the magnetic fluctuations of Fe clusters has a dominant effect on the behavior of of the magnetic compounds at low temperatures. On the other hand, S is not sensitive to the magnetic state and the external magnetic field, which is related to the energy dependence of magnetic scattering at the Fermi level.