Influence of Pellet Compaction Pressure on the Physical Properties of La0.7Ba0.3MnO3 Manganite

Perovskite manganite La0.7Ba0.3MnO3, synthesized by ionic coordination reaction method (ICR) was compacted into pellets under different compaction pressures (Pc) and sintered at a temperature of 1150°C for 10h under a flow of O2. X-ray diffraction (XRD) data reveal that the samples can present simultaneously two phases - a rhombohedral structure with space group R3c and an orthorhombic structure with space group Pnma. Scanning electron microscopy (SEM) images show that, for this sintering temperature, the particle size and shape can be modified depending on the compaction pressure (Pc). Magnetization measurements show that the saturation magnetization and Curie temperature increase with Pc. The enhancement of the ferromagnetic properties of perovskite manganites La0.7Ba0.3MnO3 as a function of the compaction pressure is explained by an increase in the rhombohedral/orthorhombic structure ratio caused by this effect.

通过离子配位反应法（ionic coordination reaction method, ICR）合成的钙钛矿型锰氧化物La₀.₇Ba₀.₃MnO₃，先在不同压制压力（Pc）下压制成压片，随后于氧气流通氛围下以1150℃烧结10小时。X射线衍射（X-ray diffraction, XRD）测试结果表明，样品可同时呈现两相结构：空间群为R3c的菱面体结构与空间群为Pnma的正交晶结构。扫描电子显微镜（Scanning electron microscopy, SEM）图像显示，在该烧结温度条件下，颗粒的尺寸与形貌可随压制压力（Pc）的变化进行调控。磁化性能测试结果显示，饱和磁化强度与居里温度均随压制压力（Pc）的升高而增大。钙钛矿型锰氧化物La₀.₇Ba₀.₃MnO₃的铁磁性能随压制压力增强的现象，可通过该工艺引发的菱面体/正交晶结构占比提升得到合理解释。