Synthesis, Structure and Magnetic Properties of Nanowires Made from Alloys of Iron-Group Metals

The dependence of the structure and composition of nanowires made from FeCo and FeNi alloys on the composition of the electrolyte and the conditions of preparation by the method of matrix synthesis is established. FeNi nanowires contain significantly more iron than is contained in the growth solution, while in the case of FeCo, the composition corresponds to that of the electrolyte. It is shown that the structure of nanowires changes from FCC to BCC at an iron concentration higher than 25% for FeNi and 20% for FeCo. A comparison is made with pure Co nanowires, in which a hexagonal close packed (HCP) structure can be obtained with an increase in the pH value of the electrolyte. The dependence of the magnetic properties of FeCo and FeNi nanowires on the composition and diameter, respectively, is studied. The maximum coercive force in FeCo nanowires is achieved with an equiatomic composition (45% Fe) and with the maximum cobalt content. A decrease in the diameter of FeNi nanowires (from 200 to 30 nm) leads to a great increase in the coercive force (from 80 to 950 Oe).