Characteristics of nano-sized La_0.75Sr_0.25Cr_0.5Mn_0.5O₃ powders prepared by spray pyrolysis

Nano-sized La_0.75Sr_0.25Cr_0.5Mn_0.5O₃ (LSCM) powders were prepared by calcination of precursor powders obtained by spray pyrolysis. The precursor powders prepared from the spray solutions with citric acid or ethylene glycol had a spherical shape and a hollow morphology. The precursor powders were converted to nano-sized LSCM powders after calcination at high temperatures. The mean sizes of the LSCM powders calcined at temperatures of 700 and 800°C were 70 and 90 nm. However, the mean sizes of the LSCM powders calcined at temperatures of 1000 and 1100°C were 0.38 and 0.78 μm. The sintered pellets formed from the LSCM powders obtained from the spray solution without an organic additive had high porosities. The hollow structure of the LSCM powders produced the sintered pellets with high porosities. The sintered pellets obtained from the nano-sized LSCM powders had dense structures and low porosities. However, the sintered pellets obtained from the submicrometre-sized LSCM powders had regular pore structures and high porosities.