水热法制备CoFe_2O_4纳米颗粒及其穆斯堡尔谱与磁性能研究

摘要

Good crystallinity and uniform CoFe2O4 different synthesis temperatures without further calcination. The synthesized samples at different temperatures were studied by XRD, SEM, Mossbauer spectra and PPMS. The results show that as the synthesis temperature increases, the crystallinity, size and the saturation magnetization of the CoFe2O4 crystalline nanoparticles gradually increase. When the synthesis temperature reached 500℃, the saturation magnetization of the CoFe20, nan- oparticles reached 64.1A · m2/kg, close to the bulk CoFe204 （72A·m2/kg）. The results of Mossbauer spectrum indicate that when the grain size is greater than the size of the critical size of superparamagnetic, the superparamagnetism of the samples disappear. The proportion of Fe3＋ ion in B-site and the magnetic properties increase with synthesis temperature increasing.%用水热法在不同温度下制备结晶性较好、颗粒均一的CoFe2O4纳米颗粒,无需进一步煅烧。利用X射线衍射仪（XRD）、场发射扫描电镜（SEM）、穆斯堡尔谱仪和综合物性测量系统（PPMS）对不同温度下合成的样品进行表征。结果表明,随着合成温度的升高,CoFe2O4纳米颗粒的结晶性增强,粒径逐渐增大,样品的饱和磁化强度逐渐增强。当合成温度为500℃时,CoFe2O4纳米颗粒的饱和磁化强度达到64.1A.m2/kg,与块体的CoFe2O4（72A.m2/kg）接近。穆斯堡尔谱分析表明,当晶粒粒径超过了超顺磁性的临界尺寸,样品的超顺磁性消失,随着合成温度的升高,B位上Fe3＋离子的比例增高,磁性能增强。