Effects of synthesis conditions on Curie temperature of La0.75Sr0.25MnO3 fine particles formed by ultrasonic spray pyrolysis

Manganese perovskite La0.75Sr0.25MnO3 (LSM) fine particles were synthesized by an ultrasonic spray pyrolysis method at various synthesis temperatures (Ts), reaction times (tr), and source solution concentrations (Ctotal) to clarify the effects of these synthesis conditions on their Curie temperature Tc and maximum particle temperature attained by magnetic heating at Thmax. At constant Ctotal, the Tc of synthesized LSM particles was increased from 288.6 to 363.5 K (15.6 to 90.5 ?C) by increasing Ts from 1073 to 1627 K (800 to 1400 ?C), and was increased from 281.8 to 339 K (8.89 to 66 ?C) by increasing tr from 2.4 to 19 s. When the AC magnetic field was applied, the particles generated heat, and the particle temperature Th increased with time for t < about 2 min, and then attained constant Thmax near Tc. Thmax increased with increasing Tc. The LSM particles produced at Ts = 1213 K, Ctotal = 0.5 mol L?1, and tr = 9.4 s had Thmax = 316.6 K (43.6 ?C), which is within the temperature range of 316?318 K (43?45 ?C) for hyperthermia therapy for cancer.