Mokkath Junais Habeeb
Quantum Nanophotonics Simulations Lab, Department of Physics, Kuwait College of Science And Technology, 7th Ring Road, P.O. Box 27235, Kuwait.
Phys Chem Chem Phys. 2020 Mar 21;22(11):6275-6281. doi: 10.1039/c9cp06905d. Epub 2020 Mar 4.
The effect of particle size and chemical order on the temperature-dependent magnetic properties of Fe@Ni and Ni@Fe core-shell nanoparticles is studied in the framework of a classical spin Hamiltonian and Monte Carlo simulations. We found that the mean temperature-dependent magnetization and magnetic-ordering temperature are strongly affected by both the particle size (in size range of 4 to 16 nm) and core-shell chemical order. As a main result, we report the depression of the magnetic ordering-temperature with decreasing size of the elemental Fe and Ni nanoparticles. More specifically, in the case of Fe and Ni nanoparticles, the magnetic-ordering temperature is lowered by 40 (195 K) to 300 (175 K) compared to the bulk value for nanoparticle diameters ranging from 16 to 4 nm, respectively, consistent with previous theoretical data. We further provide a comprehensive insight into the magnetic properties of Fe@Ni and Ni@Fe nanoparticles, unveiling a rich and distinct magnetic-ordering temperature and spin structure that emphatically depends on the core/shell ratio.
在经典自旋哈密顿量和蒙特卡罗模拟的框架下，研究了粒径和化学有序性对Fe@Ni和Ni@Fe核壳纳米粒子温度依赖磁性的影响。我们发现，平均温度依赖磁化强度和磁有序温度都受到粒径（4至16纳米范围内）和核壳化学有序性的强烈影响。作为主要结果，我们报道了随着元素Fe和Ni纳米粒子尺寸减小，磁有序温度降低。更具体地说，对于Fe和Ni纳米粒子，与体材料值相比，纳米粒子直径分别从16纳米减小到4纳米时，磁有序温度降低了40（195K）至300（175K），这与先前的理论数据一致。我们进一步全面深入地研究了Fe@Ni和Ni@Fe纳米粒子的磁性，揭示了丰富且独特的磁有序温度和自旋结构，其强烈依赖于核/壳比。
