Studies of electrical transport properties of Sr2Fe(Mo,V)O6 compound

Systematic study of X-ray, electrical resistivity (rho) and thermoelectric power (TEP, S) on polycrystalline Sr2FeMo1-xVxO6 (X = 0-0.5) samples have been performed over a wide temperature range (20-900 K). From the analysis of the resistivity data we find that the temperature dependence of rho of the undoped Sr2FeMoO6 (x = 0) sample is similar to that of metallic sample. For the doped samples (x not equal 0) rho scales well with T-2 nature only in the high temperature region and the analysis suggests that the electron-electron scattering plays a major role governing the conduction mechanism. At the low temperature semiconducting region rho(T) data starts deviation from the T-2 variation and can be explained considering three-dimensional variable range hopping (VRH) processes implying weak localization of the charge carriers. For all the samples with x > 0 thermoelectric power (S) measurement reveals almost linear temperature dependencies similar to metallic samples. For x = 0 sample the linear variation of S(T) is observed only in the temperature interval (170 K < T < 320 K) and below 170 K S(T) shows a small curvature down to 77 K. At T < 100 K a sign change of S from negative to positive values has been observed for samples with x = 0.1-0.3. The estimated Fermi energy (E-F) calculated from the slope of S(T) curves lies in the range 1.12-0.61 eV for x = 0.0-0.5 samples, respectively. (C) 2003 Elsevier B.V. All rights reserved.