Novel synthesis and magnetocaloric assessment of functional oxide perovskites

The magnetic entropy change associated with the ferromagnetic Curie transition has been studied in La_0.85Sr_0.15MnO₃ (LSM) perovskites obtained by both the citrate-nitrate gel autoignition and combustion thermal spray techniques. A modest magnetic entropy change can be observed in La_0.85Sr_0.15MnO₃ by sintering the precursor-derived powder at 1200 °C for 16 h or by combustion spraying the solution precursor onto an Al substrate and annealing at 800 °C for 6 h. The combustion thermal spray process with rapid deposition rates and relatively low deposition temperature directly produces a microcrystalline perovskite phase. This microcrystalline powder can be processed more rapidly and at lower temperatures than that derived from the sol-gel syntheses process to produce material with fine crystallinity and an obvious magnetocaloric effect.