用正电子湮没寿命谱研究锰锌铁氧体纳米晶的缺陷结构

On defects structure of manganese zinc ferrite nanocrystallines by positron annihilation lifetime spectroscopy

采用溶胶-凝胶法,在不同退火温度下得到了3种不同粒径的锰锌铁氧体纳米晶.利用X射线衍射研究了纳米晶的晶体结构和粒径,借助正电子湮没寿命谱仪讨论了纳米晶的缺陷随粒径的变化.结果显示,所得锰锌铁氧体纳米晶为立方尖晶石结构,且随着温度的升高纳米晶不断长大;随着粒径的增大,纳米晶的表面缺陷减小,晶界间的自由体积发生复合.

Three types of manganese zinc ferrite nanocrystallines with different grain sizes are prepared by sol-gel process at different annealing temperatures. Crystal structure and grain size are investigated though X-ray diffraction, and positron annihilation lifetime spectroscopy investigation is carried out to study the changes in defects of nanocrystallines with grain size. The results suggest that manganese zinc ferrite nanocrystallines with cubic spinel structure are synthesized, and with annealing temperature increment, the nanocrystallines obviously grow up. With the augmentation of grain size, surface defects of the manganese zinc ferrite nanocrystallines minish, and intergranular free volume combines.