Department of Chemistry, Birla Institute of Technology and Science, Pilani, K. K. Birla, Goa Campus, Zuarinagar, 403726, Goa, India.
Defence Metallurgical Research Laboratory, Hyderabad 500058, India.
J Nanosci Nanotechnol. 2020 Feb 1;20(2):983-990. doi: 10.1166/jnn.2020.16891.
Low temperature preparation of nanostructured CoCrFeO₄ (0<x <1) spinel ferrites has been successfully achieved via citric acid assisted sol-gel method at 350 °C. Phase purity and structural studies were investigated using XRD and IR spectroscopy. Lattice parameters of the spinel ferrites decrease with the progressive increase in Cr content (x) in CoCr FeO₄. IR bands at ~600 cm and ~400 cm confirm distinct metal-oxygen vibrations corresponding to tetrahedral and octahedral sites, respectively. Average crystallite sizes and SEM particle sizes were found to be in the range of 25-13 nm and 86-117 nm for CoCrFeO₄ materials, respectively. The values of saturation magnetizations () and coercivities (H) decreases, i.e., from 73.8 emu/g to 16.8 emu/g and from 1467 Oe to 71 Oe, with the increase in the value of x, i.e., from = 0 to = 1.0, in CoCrFeO₄, respectively. The observed changes in magnetic properties have been explained on the basis of altered composition, magnetic structure, fine particle size, and surface effects. These results are also supported by our Mössbauer spectroscopic investigation.
采用柠檬酸辅助溶胶-凝胶法在 350°C 成功制备了 CoCrFeO₄（0<x <1）纳米结构尖晶石铁氧体。采用 XRD 和红外光谱研究了物相纯度和结构。尖晶石铁氧体的晶格参数随 CoCrFeO₄中 Cr 含量（x）的逐渐增加而减小。在600 cm 和400 cm 处的 IR 带分别对应于四面体和八面体位置的明显金属-氧振动。CoCrFeO₄ 材料的平均晶粒尺寸和 SEM 粒径分别在 25-13nm 和 86-117nm 范围内。饱和磁化强度（）和矫顽力（H）的值随着 x 值的增加而减小，即从 73.8 emu/g 降低到 16.8 emu/g，从 1467 Oe 降低到 71 Oe，在 CoCrFeO₄ 中，x 从 = 0 增加到 = 1.0。观察到的磁性能变化基于改变的组成、磁结构、小颗粒尺寸和表面效应来解释。我们的穆斯堡尔光谱研究也支持这些结果。
