Synthesis, microstructure, and electrical properties of the delafossite compound CuGaO2

The electrical properties and microstructural characteristics of solid-state synthesized CuGaO2 ceramics were investigated. Undoped CuGaO2 ceramics exhibited p-type conductivity with a Seebeck coefficient of 780 μV/K and a room temperature conductivity of 0.0033 S/cm. Examination of the microstructure of CuGaO2 ceramics revealed the existence of thin laminar twins oriented along the {0 0 0 1} basal plane with thickness varying from several to several tens of nanometers. Doping with Ni2+ and Mg2+ did not result in a significant increase in conductivity and doping with Sn4+ resulted in a remarkable decrease in conductivity. With evidence from diffraction data on Sn-doped ceramics, it is proposed that the Sn4+ was ionically compensated with Cu vacancies.