缺陷與磁性能
(中南大學(xué) 化學(xué)化工學(xué)院， 長(zhǎng)沙 410083)
摘 要: 采用XPS及氧化還原滴定等手段確定了一種鋅錳鐵氧體納米晶的離子分布式。采用XRD測(cè)定的樣品晶格常數(shù)（a測(cè)=0.8431nm）與通過(guò)理論計(jì)算的結(jié)果（a=0.8393nm）十分接近。樣品在350, 450和700℃經(jīng)過(guò)4h熱處理后， 離子分布數(shù)相應(yīng)發(fā)生了變化： 陽(yáng)離子空位數(shù)e在350℃時(shí)達(dá)到最大值0.05520; 晶格常數(shù)a隨晶體陽(yáng)離子空位數(shù)e的增加而增大， 當(dāng)e大于0.05時(shí)， 晶格常數(shù)a的增加變緩。 熱處理溫度不同， 樣品比飽和磁化強(qiáng)度σm 相應(yīng)改變， 在350℃有最小值58.5Am2/kg。 理論計(jì)算與實(shí)驗(yàn)結(jié)果表明， 樣品的比飽和磁化強(qiáng)度σm與晶體中陽(yáng)離子空位數(shù)e和次晶格上各價(jià)態(tài)的離子分布方式有關(guān)。
關(guān)鍵字: 鋅錳鐵氧體納米晶; 離子分布; 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
