缺陷与磁性能
(中南大学 化学化工学院, 长沙 410083)
摘 要: 采用XPS及氧化还原滴定等手段确定了一种锌锰铁氧体纳米晶的离子分布式。采用XRD测定的样品晶格常数(a测=0.8431nm)与通过理论计算的结果(a=0.8393nm)十分接近。样品在350, 450和700℃经过4h热处理后, 离子分布数相应发生了变化: 阳离子空位数e在350℃时达到最大值0.05520; 晶格常数a随晶体阳离子空位数e的增加而增大, 当e大于0.05时, 晶格常数a的增加变缓。 热处理温度不同, 样品比饱和磁化强度σm 相应改变, 在350℃有最小值58.5Am2/kg。 理论计算与实验结果表明, 样品的比饱和磁化强度σm与晶体中阳离子空位数e和次晶格上各价态的离子分布方式有关。
关键字: 锌锰铁氧体纳米晶; 离子分布; 缺陷; 磁性能
particles prepared by hydrothermal method
(College of Chemistry and Chemical Engineering,
Central South University, Changsha 410083, China)
Abstract:The ion distribution model of ZnMn ferrite was determined by XPS and oxidimetry methods. The crystal lattice constant measured by XRD (0.8431nm )is close to that of calculated(0.8393nm) by the ion distribution model. The number of ion distribution in the model changes after heat treatment at 350, 450 and 700℃ respectively, due to the different ability of occupying A and B sublattice of different metal ions. The metal ion vacancy e has a maximum value of 0.05520 at 350℃. The lattice constant a increases with the increase of metal ion vacancy e and at e=0.05 the increasing tendency becomes slow. The specific saturation magnetization σm alters with the heat treatment temperature and has a minimum value of 58.5A·m2/kg at 350℃. Theoretical calculation and experimental results show that the specific saturation magnetization σm is related with metal ion vacancy e and the crystal ion distribution model.
Key words: ZnMn ferrite nanoscale particles; ion distribution; defect; magnetic property