中文摘要：

采用以硫酸锰、硫酸锌、硫酸亚铁以及柠檬酸为原料的溶胶．凝胶方法制备热敏锰锌铁氧体。在900℃煅烧，得到锰锌铁氧体的粉体．将粉体压成环形样品，在平衡气氛下，1350℃烧结。采用扫描电镜（SEM）分析锰锌铁氧体烧结体的显微结构；用HP4192，测量从室温到150℃的烧结体的磁导率。结果表明在800℃热处理，得到尖晶石结构的锰锌铁氧体粉体。在平衡气氛下，1300℃烧结2h，得到尖晶石结构的锰锌铁氧体烧结体。扫描电镜（SEM）图谱显示烧结体显微结构致密，晶粒平均尺寸大约在5～10μm；锰锌热敏铁氧体的磁导率μi在居里温度附近发生突变，说明锰锌热敏铁氧体的磁性由铁磁相转变为顺磁相；在铁离子含量不变的条件下，随着锌离子含量（Zn2＋）的增加，锰离子含量（Mn2＋）的减少，锰锌热敏铁氧体的居里温度降低；锰锌热敏铁氧体的磁导率胁，随着锌离子含量（Zn2＋）的增加而降低。

英文摘要：

Thermal sensitive manganese zinc ferrites with various stoichiometry were prepared from sol-gel-derived powders. Manganese sulfate, zinc sulfate, ferrous sulfate and the citric acid were selected as raw materials in the sol-gel process. Manganese zinc ferrites powders were obtained after calcined at 900 ℃. Under the balanced atmosphere, the ring-like samples were sintered at 1350℃. The microstructure of manganese zinc ferrites was analyzed by X-ray diffraction （XRD） and scanning electron microscopy （SEM）; with HP4192 LCR meter, the magnetic properties of the samples were obtained from room temperature to 150℃. The result indicated that manganese zinc ferrites powder was the spinel structure after calcined at 800℃ in air for 2 h. Under the balanced atmosphere, after sintered at 1350 ℃ for 2 h, the spinel structure remained. The SEM showed the microstructure of the samples was compact and the grain size was approximately 5 μm. The magnetic permeability of thermal sensitive manganese zinc ferrites had a sudden change near the Curie temperature, which can be explained by the ferromagnetic to paramagnetic phase transition. It was found that Tc reduced linearly with increasing Zn2＋ extent when the content of Fe2O3 was fixed.