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用乙二醇为溶剂,用三氯化铁、二氯化钴和醋酸铵为起始反应试剂,通过溶剂热反应首次合成了纳米结构CoxFe3-xO4多孔微球.用X射线衍射仪(XRD)、透射电子显微镜(TEM)和扫描电子显微镜(SEM)表征样品的结构和形貌,结果表明,所制备的单分散CoxFe3-xO4多孔微球为立方多晶结构,其直径约300nm,是由约30nm颗粒组装而成.用振动样品磁强计(VSM)测量了CoxFe3-xO4多孔微球的室温和变温磁性,室温下其饱和磁化强度Ms随Co2+含量x的增加先升后降,矫顽力HC随Co2+含量x的增大而上升;居里温度TC随Co2+含量x的变化趋势为先增后降;低温下CoxFe3-xO4多孔微球存在显著的正交换偏置效应,这种奇特的现象还未见报道,这与其由纳米颗粒组装的多孔微球结构有密切关系.
The nanostructured CoxFe3-xO4 porous microspheres were synthesized by solvothermal reaction using ethylene glycol as the solvent and ferric chloride, cobalt (II) chloride and ammonium acetate as starting reagents. XRD, , Transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results show that the prepared monodisperse CoxFe3-xO4 porous microspheres have a cubic polycrystalline structure with a diameter of about 300 nm, 30nm particles were assembled.The room temperature and temperature-dependent magnetic properties of CoxFe3-xO4 porous microspheres were measured by vibrating sample magnetometer (VSM). The saturation magnetization Ms at room temperature increased first and then decreased with the increase of Co2 + content x. The coercivity HC increases with the increase of Co2 + content x. The Curie temperature TC increases first and then decreases with the increase of Co2 + content x. The strange crossover effect of CoxFe3-xO4 porous microspheres exists at low temperature It has not been reported, which is closely related to the structure of porous microspheres assembled by nanoparticles.