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采用非晶态多核配合的方法制备了(La0.47Gd0.2)Sr0.33MnO3纳米颗粒,用XRD、HRTEM和MPMS等手段对纳米颗粒的微观结构和磁性能进行研究。XRD和SAD分析表明,所有的样品都具有单相钙钛矿结构;TEM分析表明,经过600,800和1000℃烧结10h后的样品颗粒尺寸分别为40～50nm,90～100nm和140～150nm。样品的磁学性能结果表明:(La0.47Gd0.2)Sr0.33MnO3纳米颗粒的居里温度TC(298K)基本上不随颗粒尺寸的变化而变化,而相对磁制冷能力取决于颗粒尺寸;颗粒尺寸为90～100nm的(La0.47Gd0.2)Sr0.33MnO3纳米颗粒的相对磁制冷能力最大,可以作为室温下使用的磁制冷工质侯选材料。
(La0.47Gd0.2) Sr0.33MnO3 nanoparticles were prepared by amorphous multi-core coordination method. The microstructure and magnetic properties of the nanoparticles were investigated by XRD, HRTEM and MPMS. XRD and SAD analysis showed that all the samples had a single-phase perovskite structure. TEM analysis showed that the particle sizes of the samples were 40-50nm, 90-100nm and 140-150nm respectively after sintering at 600,800 and 1000 ℃ for 10h. The magnetic properties of the samples show that the Curie temperature TC (298K) of (La0.47Gd0.2) Sr0.33MnO3nanoparticles basically does not change with the particle size, while the relative magnetic refrigeration capacity depends on the particle size; the particle size (La0.47Gd0.2) Sr0.33MnO3nanoparticles with 90 ~ 100nm have the largest relative magnetic refrigeration capacity and can be used as magnetic refrigerant candidates at room temperature.