Synthesis and measurement of structural and magnetic properties of K-doped LaCoO3 perovskite materials

Polycrystalline La1−xKxCoO3 (0 ≤ x ≤ 0.2) rare earth cobaltates have been synthesized by a solution combustion method using glycine as a fuel. The synthesized ceramic materials were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and magnetic measurements and studied for physical properties, such as photocatalytic activity. FTIR measurements in conjunction with XRD showed that phases beyond 10% K doping are accompanied by small amounts of impurities. Chemical titrations show the presence of Co4+ and account for the Co3+-Co4+ mixed-valency of the system. The parent LaCoO3 shows spin-glass transition at low temperatures, whereas doped samples show transition from spin-glass behavior to paramagnetic ordering on progressive doping of K. “Mixed-conductor” nature of these ceramics positions them as viable candidates for solid oxide fuel cell (SOFC) applications.