高压下热处理温度对CoFe_2O_4/SiO_2结构和磁性的影响

The Effects of Annealing Temperature on Structure and Magnetic Properties of CoFe_2O_4/SiO_2 under High Pressure

对采用溶胶凝-胶法制备的(CoFe_2O_4)0.7/(SiO_2)_(0.3)纳米复合粉末进行了高压(5 GPa)处理,研究了高压下热处理温度对样品结构和磁性的影响.结果表明,在5 GPa压力下,经600℃热处理后样品中没有形成尖晶石铁氧体,当温度达到800℃时才有CoFe_2O_4形成.随着热处理温度的升高,CoFe_2O_4纳米颗粒的平均晶粒尺寸从69 nm增大到287 nm,样品的饱和磁化强度从39.6 A·m^2/kg增大到51.2 A·m^2/kg,而矫顽力从44.6 k A/m减小到11.0 k A/m.样品磁性是变化与CoFe_2O_4纳米颗粒的增大有关系.

The effects of annealing temperature on the structure and magnetic properties for（ CoFe2O4 ） 0.7/ （ SiO2 ） 0.3 nanoeomposites prepared by sol-gel model under high pressure have been investigated. The research shows that there is without spinel ferrite when annealing temperature is 600 ℃ under the pressure being 5 GPa. When the temperature reaches 800 ℃, CoFe2O4 nanoparticles appear. With the increase of annealing temperature, the average grain size of CoFe/O4 nanopartieles increases from 69 to 287 nm, the saturation magnetization of the samples increases from 39.6 to 51.2 A · m2/kg, the coercive decreased from 44.6 to 11.0 kA/m. The changes of magnetic for the samples have relations with the increasing of nanopartieles.