Electrical transport properties of Ca3－xAgxCo4O9(x=0—0.05) oxide

The electrical transport properties of Ca3Co4O9 could be modified by doping in the Ca site. The Ca site doped Ca3-xAgxCo4O9(x=0—005) bulk samples were fabricated by citric acid sol-gel and spark plasma sintering method. The resulting samples were analyzed by X-ray power diffraction, scanning electron microscopy and electrical constant measurement. The results showed that all samples were single phased, the prefered orientation was lowered by Ag doping for Ca. The x=003 sample exhibited highest grain orientation among doped samples, which exhibited layered microstructure. Its electrical resistivity was increased and then decreased slightly by Ag doping, but the transport mechanism was not changed. However, the doped samples exhibited high electrical resistivity caused by changed electronic structure by Ag doping for Ca. The x=004 sample exhibited highest electrical resistivity in the measuring temperature region with the highest value 146 mΩ·cm at 973 K.