The high-quality oleic acid coated cobalt ferrite (OCF) nanopowders were prepared by hydrothermal route at 60 °C, 120 °C and 180 °C temperatures. The average crystallite sizes of 5.2 ± 0.07 nm, 13.3 ± 0.19 nm and 18.9 ± 0.23 nm were evaluated for OCF-60, OCF-120 and OCF-180. The SEM images of OCF exhibits agglomerated nanoparticles of roughly spherical shape. Optical energy gap was estimated and found to be enhanced from 1.8 to 2.3 eV with decreasing particle size. The area ratio $A_{v2}$ of phonon modes occurred at 447 and 600–613 cm⁻¹ are correspond to octahedral and tetrahedral sites, respectively. The enhancement in saturation magnetization $M_S$ was observed from 44.64 to 76.66 (emu/g) owing to decrease in area ratio $A_{v2}$. Value of spin-spin correlation function was found to be decreased from 1.60 to 0.93 with increase in $M_S$/size. A strong correlation between magnetic and optical properties with particle size was observed.

通过水热法在60°C，120°C和180°C的温度下制备高质量的油酸包覆的钴铁氧体（OCF）纳米粉。OCF-60，OCF-120和OCF-180的平均微晶尺寸分别为5.2±0.07 nm，13.3±0.19 nm和18.9±0.23 nm。OCF的SEM图像显示出大致球形的团聚纳米颗粒。估计了光能隙，发现随着粒子尺寸的减小，光能隙从1.8 eV提高到2.3 eV。面积比${\mathrm{一种}}_{v2}$在447和600–613 cm ^-1处发生的声子模式分别对应于八面体和四面体位置。饱和磁化强度的提高${\mathrm{中号}}_{\mathrm{小号}}$ 由于面积比的减少，从44.64降至76.66（emu / g） ${\mathrm{一种}}_{v2}$。发现自旋-自旋相关函数的值从1.60降低到0.93，${\mathrm{中号}}_{\mathrm{小号}}$/尺寸。观察到磁性和光学性质与粒径之间的强相关性。