Abstract Co2FeAl (CFA) nanoparticles (NPs) of different sizes were synthesized by chemical route. The effect of the size of NPs upon the structure and magnetization compared to its bulk counterpart was investigated. The structure and composition were determined from X-ray diffraction (XRD) and electron microscopy. XRD analysis shows that the samples are having single (A2-type) disordered phase. Magnetization measurements suggest that the samples are soft ferromagnetic in nature with very low coercivity. Enhanced magnetic properties like saturation magnetization, coercive force, retentivity, and Curie-temperature are observed with a decrease in particle size. The effect of particle size on hysteresis losses is also discussed. The smallest particles of size 16 nm exhibited the highest saturation magnetization and transition temperature of 180.73 emu/g and 1261 K, respectively. The origin of enhancement in magnetization of Co2FeAl nano-alloy is attributed to the strong Co-Co exchange interaction due to disorder present in the systems.

中文翻译：

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无序 Co2FeAl Heusler 合金纳米颗粒的尺寸相关结构和磁性能

摘要 通过化学途径合成了不同尺寸的Co2FeAl(CFA)纳米颗粒(NPs)。研究了 NPs 的尺寸对其结构和磁化强度的影响与其体相比较。结构和组成由 X 射线衍射 (XRD) 和电子显微镜确定。XRD 分析表明样品具有单一（A2 型）无序相。磁化测量表明，样品本质上是软铁磁性的，矫顽力非常低。随着颗粒尺寸的减小，观察到增强的磁性能，如饱和磁化强度、矫顽力、保持力和居里温度。还讨论了粒度对滞后损耗的影响。尺寸为 16 nm 的最小颗粒表现出最高的饱和磁化强度和 180 的转变温度。分别为 73 emu/g 和 1261 K。Co2FeAl 纳米合金磁化强度增强的起源归因于系统中存在的无序导致的强 Co-Co 交换相互作用。