Tunable Synthesis, Growth Mechanism, and Magnetic Properties of La_0.5Ba_0.5MnO₃

Abstract

La 0.5 Ba 0.5 MnO 3 products with novel flowerlike, microcube, and nanocube structures were successfully synthesized by a simple hydrothermal route by controlling the alkalinity of the reaction solutions. The synthesized products were systematically studied by X-ray powder diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy. The results showed that the formation of the flowerlike structures with a layer assembly experienced a nucleation−aggregation−crystallization growth process, while the cubic structures experienced a nucleation−crystallization growth process due to the effect of different alkalinity in the reaction solutions. The higher alkalinity also led to a decrease in the size in the cubic structures. Suitable temperature and pressure were demonstrated to be crucial to the formation of the flowerlike structures by carrying out further control experiments. The measurement of the magnetic properties of three samples obtained at different alkaline conditions indicated that the size of the La 0.5 Ba 0.5 MnO 3 products had an obvious influence on their properties; however, the dependence of the properties upon the morphology of the La 0.5 Ba 0.5 MnO 3 products was minor.