Nanocrystalline Mn-Zn ferrite nanopowders (Mn_0.5Zn_0.5Fe₂O₄) were synthesized by co-precipitation technique and post-fabrication annealing has been performed at different temperature ranges from 400 to 700 °C for 2 h. The effect of annealing on morphology, crystalline phase formation, cation distribution, lattice constant, particle size, magnetic properties, and optical properties was studied by scanning electron microscopy (SEM), x-ray diffraction (XRD), vibrating sample magnetometer (VSM), and UV-visible spectroscopy (UV-Vis) respectively. The crystallite size increased from 14 to 24 nm with the annealing temperature owing to the grain growth process or more technically we say Ostwald ripening mechanism. The decomposition of ferrites at low-temperature results in the formation of hematite Fe₂O₃ eventually reduced the magnetic properties of ferrites. The hematite, impurity phase, started to dissolve or converted into the ferrite phase after 600 °C. The sample annealed at 700 °C shows a better crystalline structure, phase formation, and larger magnetization compared to the other ferrite samples. The improved magnetic behavior after heat treatment is due to the better alignment of domains at the cost of the grain growth process. The UV-Vis spectroscopy result revealed the maximum absorbance at 380 nm.

纳米晶Mn-Zn铁氧体纳米粉（Mn _0.5 Zn _0.5 Fe ₂ O ₄）是通过共沉淀技术合成的，并且在400至700°C的不同温度范围内进行了2小时的后加工退火。通过扫描电子显微镜（SEM），X射线衍射（XRD），振动样品磁强计（VSM）研究了退火对形态，结晶相形成，阳离子分布，晶格常数，粒度，磁性和光学性质的影响。 ，和紫外可见光谱（UV-Vis）。由于晶粒的生长过程，随着退火温度的增加，晶粒尺寸从14nm增加到24nm，或者从技术上讲，我们称奥斯特瓦尔德成熟机制。铁素体在低温下的分解导致赤铁矿Fe ₂ O ₃的形成最终降低了铁氧体的磁性。600℃后，赤铁矿杂质相开始溶解或转变为铁素体相。与其他铁氧体样品相比，在700°C退火的样品表现出更好的晶体结构，相形成和更大的磁化强度。热处理后改善的磁性能归因于以晶粒生长过程为代价的磁畴更好地对准。紫外-可见光谱结果显示在380 nm处有最大吸光度。