Effect of alkaline earth dopant on density, mechanical, and electrical properties of Cu 0.97 AE 0.03 CrO 2 (AE = Mg, Ca, Sr, and Ba) delafossite oxide

CuCrO 2 and Cu 0.97 AE 0.03 CrO 2 (AE = Mg, Ca, Sr, and Ba) polycrystalline materials have been prepared through the classical solid state route. CuCrO 2 is the major phase in all cases, with larger grain sizes when the alkaline earth dopant is larger. Doping also promotes the formation of secondary phases, which appear in the grain boundaries in the Ca, Sr, and Ba doped samples. Density has been drastically improved through doping, reflected in lower electrical resistivities and higher mechanical properties than the measured in undoped samples. In spite of a relatively high decrease of Seebeck coefficient, all doped samples reached higher power factor values than the undoped ones in the whole measured temperature range. The highest power factor has been reached in Mg doped samples, 0.32 mW/K 2 m at 800 °C, which is among the highest obtained so far in randomly oriented polycrystalline CuCrO 2 materials.