Abstract

Several types of nanowires from alloys of various compositions obtained by the method of matrix synthesis based on track membranes are investigated in this study. Electrolytes are selected to obtain nanowires of the desired composition. The control of electrodeposition by chronoamperograms has made it possible to systemically vary the geometric parameters and morphology. The topographies of the resulting nanowire arrays and their elemental composition are studied using electron microscopy with an X-ray spectral analyzer. The magnetic properties of the samples (hysteresis loops and the coercive force and residual magnetization values) are measured on a vibrating magnetometer. The structures of binary alloys are studied, and the dependence of the coercive force on the composition is analyzed for nanowires of FeCo alloys. The resulting dependence has two maxima (the coercive force is about 300 Oe) at an equiatomic composition and at a cobalt content of about 90%. For Fe_0.3Co_0.7 nanopowders, the dependence of the coercive force on the diameter is studied, and a sharp increase in the former from 200 to 1300 Oe is found with a decrease in the nanowire diameter from 100 nm to 30 nm, respectively. The increase in the coercivity with a decrease in the diameter is caused by the formation of single-domain crystallites, the processes of magnetization reversal of which are associated with uniform rotation of the magnetization. For nanowires made of FeNi alloys, the effect of the aspect ratio on the coercive force is revealed. As found from the results of studying ternary alloys of the FeCoCu system, the addition of copper substantially increases the coercive force, which reaches a maximum (500 Oe) at a copper content of about 5%. The obtained X-ray diffraction data suggest that the effect of an increase in the coercive force is associated with the formation of fine-grained inclusions based on copper, which leads to effective retardation of domain walls. The obtained data expand the range of possibilities for controlling the magnetic properties of NW arrays prepared by template synthesis.

中文翻译：

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二元和三元合金纳米线：结构和磁性的相关性

摘要

本研究研究了通过基于轨道膜的基质合成方法获得的多种成分合金的几种类型的纳米线。选择电解质以获得所需组成的纳米线。通过计时电流图控制电沉积使得系统地改变几何参数和形态成为可能。使用带有 X 射线光谱分析仪的电子显微镜研究所得纳米线阵列的形貌及其元素组成。在振动磁力计上测量样品的磁性（磁滞回线和矫顽力和剩磁值）。研究了二元合金的结构，分析了FeCo合金纳米线矫顽力对成分的依赖性。所得依赖性在等原子组成和钴含量约为 90% 时有两个最大值（矫顽力约为 300 Oe）。对于铁_0.3钴_0.7纳米粉末，研究了矫顽力对直径的依赖性，发现前者从 200 到 1300 Oe 急剧增加，而纳米线直径分别从 100 nm 减小到 30 nm。矫顽力随着直径的减小而增加是由单畴微晶的形成引起的，其磁化反转过程与磁化的均匀旋转有关。对于由 FeNi 合金制成的纳米线，揭示了纵横比对矫顽力的影响。研究 FeCoCu 系三元合金的结果发现，铜的加入显着增加了矫顽力，在铜含量约为 5% 时达到最大值（500 Oe）。获得的 X 射线衍射数据表明，矫顽力增加的影响与基于铜的细晶粒夹杂物的形成有关，这导致畴壁的有效延迟。获得的数据扩大了控制模板合成制备的 NW 阵列的磁性的可能性范围。