Li Qing, Kartikowati Christina W, Iwaki Toru, Okuyama Kikuo, Ogi Takashi
Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, People's Republic of China.
JurusanTeknik Kimia, FakultasTeknik, Universitas Brawijaya, Jl. MT. Haryono 167, Malang 65145, Indonesia.
R Soc Open Sci. 2020 Apr 22;7(4):191656. doi: 10.1098/rsos.191656. eCollection 2020 Apr.
Magnetic wires in highly dense arrays, possessing unique magnetic properties, are eagerly anticipated for inexpensive and scalable fabrication technologies. This study reports a facile method to fabricate arrays of magnetic wires directly assembled from well-dispersed α-FeN/AlO and FeO nanoparticles with average diameters of 45 nm and 65 nm, respectively. The magnetic arrays with a height scale of the order of 10 mm were formed on substrate surfaces, which were perpendicular to an applied magnetic field of 15 T. The applied magnetic field aligned the easy axis of the magnetic nanoparticles (MNPs) and resulted in a significant enhancement of the magnetic performance. Hysteresis curves reveal that values of magnetic coercivity and remanent magnetization in the preferred magnetization direction are both higher than that of the nanoparticles, while these values in the perpendicular direction are both lower. Enhancement in the magnetic property for arrays made from spindle-shape α-FeN/AlO nanoparticles is higher than that made from cube-like α-FeN/AlO ones, owing to the shape anisotropy of MNPs. Furthermore, the assembled highly magnetic α-FeN/AlO arrays produced a detectable magnetic field with an intensity of approximately 0.2 T. Although high-intensity external field benefits for the fabrication of magnetic arrays, the newly developed technique provides an environmentally friendly and feasible approach to fabricate magnetic wires in highly dense arrays in open environment condition.
具有独特磁性的高密度阵列中的磁性线，对于廉价且可扩展的制造技术来说备受期待。本研究报告了一种简便方法，可直接由平均直径分别为45纳米和65纳米的分散良好的α-FeN/AlO和FeO纳米颗粒组装制造磁性线阵列。在垂直于15 T外加磁场的基底表面上形成了高度尺度为10毫米量级的磁性阵列。外加磁场使磁性纳米颗粒（MNP）的易轴取向，并导致磁性能显著增强。磁滞回线表明，在优选磁化方向上的矫顽力和剩余磁化强度值均高于纳米颗粒，而在垂直方向上这些值均较低。由于MNP的形状各向异性，由纺锤形α-FeN/AlO纳米颗粒制成的阵列的磁性能增强高于由立方体形α-FeN/AlO纳米颗粒制成的阵列。此外，组装的高磁性α-FeN/AlO阵列产生了强度约为0.2 T的可检测磁场。尽管高强度外部磁场有利于磁性阵列的制造，但新开发的技术提供了一种在开放环境条件下制造高密度阵列磁性线的环保且可行的方法。
