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在室温下用Mossbauer谱研究了具有不同晶粒尺寸、不同压力下压实的纳米晶材料LaFeO_3。结果表明,70nm的常规LaFeO_3晶粒呈反铁磁性结构,12.4nm的LaFeO_3纳米晶是较弱的反铁磁结构和较强的超顺磁结构的叠加。纳米晶材料的界面/体相和超精细磁场随着压实力而改变。16nm的LaFeO_3纳米晶的所有变化均小于12.4nm的LaFeO_3纳米晶的变化。转靶XRD结果表明,经过不同压力压实的样品发生了晶粒碎化、晶间接触及位错等现象。
The LaFeO_3 nanocrystalline material with different grain sizes and compacted at different pressures was studied by Mossbauer spectroscopy at room temperature. The results show that the conventional LaFeO_3 at 70nm has an antiferromagnetic structure, and the 12.4nm LaFeO_3 nanocrystal is a superposition of a weak antiferromagnetic structure and a strong superparamagnetic structure. The interfacial / bulk and ultrafine magnetic fields of nanocrystalline materials change with compaction. All changes of 16nm LaFeO_3 nanocrystals were less than that of 12.4nm LaFeO_3 nanocrystals. The results of XRD showed that the grain compaction, intergranular contact and dislocation occurred in the samples compacted by different pressures.