摘要
详细研究了不同压力下压制的ＮｉＦｅ２Ｏ４纳米固体材料的正电子寿命谱，分析了材料内部界面上缺陷结构随压制压力的变化，并与Ｌａ０．７Ｓｒ０．３ＭｎＯ３纳米固体的缺陷结构随压力的变化进行了比较。实验结果表明，随着压制压力的增加，ＮｉＦｅ２Ｏ４纳米固体内部界面上自由体积缺陷和微孔隙缺陷的体积均被明显地压缩了，但自由体积缺陷的压缩幅度要高得多，反映出ＮｉＦｅ２Ｏ４纳米固体界面上原子排列的有序程度在高压下逐渐增强的规律。对具有不同微结构变化特征的复合氧化物纳米固体材料，其内部的缺陷结构在高压下具有不同的变化规律，进而引起其宏观物性的不同变化。
In this paper, the positron annihilation lifetime spectra of NiFe 2O 4 nanocrystalline materials compacted under different pressures (0～4 5GPa)were measured. The variations of the defect structure of NiFe 2O 4 nanocrystalline with compacting pressure were analyzed and compared with those of La 0 7 Sr 0 3 MnO 3 nanosolids with different microstructural characteristics. The size of the interface free volume and the microvoid in NiFe 2O 4 nanocrystalline were all compressed measurably under high pressure, but the former has higher compressibility. These changes mean that the arrangement degree of order of the interface atoms of NiFe 2O 4 nanocrystalline is enhanced gradually with the increasing of compacting pressure.
出处
《高压物理学报》
CAS
CSCD
北大核心
1997年第4期245-249,共5页
Chinese Journal of High Pressure Physics
基金
NSFC和国家教委博士点基金
关键词
高压
纳米固体
正电子湮灭
缺陷
复合氧化物
high pressure, nanosolid, positron annihilation, defect structure.
