The aim of this research work was to study the structural and magnetic properties of iron oxide nanoparticles. The as-prepared sample was synthesized by a co-precipitation route and annealed at different temperatures. The annealed samples were investigated using different techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), and Mössbauer spectrometry (MS). The XRD results indicate the formation of three phases which have been identified as magnetite (Fe₃O₄), maghemite (γ-Fe₂O₃), and hematite (a-Fe₂O₃). The crystallite size was very similar for both magnetite and maghemite, and it was higher for hematite. The TEM observations showed that the particle shapes were affected by the annealing temperature (T_an). In addition, the SEM analysis revealed a wide distribution of the particle size. The magnetic measurements enabled the determination of a blocking temperature for both Fe₃O₄ and γ-Fe₂O₃ as 210 and 240 K, respectively. The Morin transition temperature was determined in the case of α-Fe₂O₃ from the magnetization and the MS measurements. The synthesized iron oxide nanoparticles can be good candidates for hyperthermia applications.

这项研究工作的目的是研究氧化铁纳米粒子的结构和磁性。制备的样品通过共沉淀途径合成，并在不同温度下退火。使用不同的技术，例如X射线衍射（XRD），透射电子显微镜（TEM），扫描电子显微镜（SEM），振动样品磁法（VSM）和穆斯堡尔光谱（MS），对退火后的样品进行了研究。XRD结果表明的，其已经被鉴定为磁铁矿三个阶段的形成（铁₃ Ò ₄），磁赤铁矿（γ-的Fe ₂ ö ₃），和赤铁矿（α-的Fe ₂ ö ₃）。磁铁矿和磁铁矿的晶粒尺寸非常相似，赤铁矿的晶粒尺寸较大。TEM观察表明，颗粒形状受退火温度（T _an）影响。另外，SEM分析显示出粒径的广泛分布。磁性测量启用阻塞温度的确定两者的Fe ₃ ö ₄和γ-的Fe ₂ ö ₃分别210和240 K，。的莫林转变温度在的情况下确定的α-Fe ₂ ö ₃根据磁化强度和MS测量 合成的氧化铁纳米粒子可以作为高温应用的良好候选者。