Effect of magnesium doping on thermoelectric and magnetic properties of copper chromite ceramic samples

We investigated thermoelectric and magnetic properties of polycrystalline CuCr1-xMgxO2 (x = 0; 0.002; 0.008; 0.015; 0.030) ceramic samples, synthesized by a special chemical homogenization method (nitrate synthesis). Temperature dependencies of magnetization were measured in magnetic field H = 1000 G. Transition temperature do not noticeably shift with variation of Mg content. Seebeck coefficient S increases with temperature for all investigated samples. At room temperature S decreases from nearly 700 mV/K in pristine material to about 250 mV/K for the copper chromite with 3at.% Mg. Heat conductivity k of all investigated samples is close to the heat conductivity of undoped CuCrO2 crystals. Resistivity of investigated samples decreases several orders of magnitude with increase of Mg content up to 3%. Temperature dependence of resistivity and Seebeck coefficient was interpreted by hopping conductivity in the presence of the Coulomb (parabolic) gap in the density of states. ? 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 17th European Thermoelectric Conference.