纳米材料Fe_2O_3的X射线衍射与正电子湮没研究  

Inveedgation of nanocrystalline material Fe_2O_3 by X ray diffraction and poaitron annihilation

作　　者：彭郁卿[1] 周诗瑶[1] 

机构地区：[1]中国科学院上海原子核研究所,上海师范大学

出　　处：《核技术》1995年第9期530-534,共5页Nuclear Techniques

摘　　要：给出了纳米材料Ｆｅ２Ｏ３的Ｘ射线衍射与正电子湮没辐射多普勒展宽的实验结果．发现样品分别经４００℃４ｈ与８００℃４ｈ退火后，原来的γ－Ｆｅ２Ｏ３均转变成α－Ｆｅ２Ｏ３，而且颗粒尺寸分别增加到３８．７ｎｍ与９２．９ｎｍ；样品的线形参数均随退火温度升高而减小；当Ｄ～Ｌ＋时，自由正电子湮没显著增加；压制压力较大的样品的缺陷浓度略有增加。The experimental results of X ray diffraction and Doppler broadening of positron annihilation radiation for nanocrystalline material Fe2O3 are presented. It is shown that when samples are annealed at 400°C for 4h and 800°C for 4h, the initial γ -Fe2O3 transforms into the α-Fe2O3, and grain diameters increase to 38.7nm and 92.9nm respectively. The line parameters of the specimen decrease with the annealing temperature. When D～L+, the fraction of free positron annihilation increases obviously. The defect concentration increases slightly for samples compacted with a higher pressure.

关 键 词：纳米材料 正电子湮滑 X射线衍射 三氧化二铁 

分 类 号：O48[理学—固体物理]