In this study we have fabricated by electrodeposition CoPt(FePt) nanowires embedded inside an array of empty holes in anodized aluminum disks. By adjusting the current density and solution composition, one can control the composition of the film to 50:50 in order to obtain the high anisotropy CoPt and FePt face centered tetragonal ${\text{(L1}}_0)$ phases. The as-made films are magnetically soft. Magnetic hardening is developed after annealing at $\text{700\hspace{0.05em}°}\mathrm{C}$ with coercivity typically in the range of 3–6 kOe. The scanning electron microscopy and transmission electron microscopy studies showed that nanowire structured CoPt and FePt with near stoichiometric composition inside an array of holes which are about 25–100 nm in diameter. A preferred perpendicular anisotropy is observed in the CoPt nanowires.

The structure, microstructure, and magnetic properties of nanostructured ${\mathrm{Sm}}_{\mathrm{2}}{\mathrm{Co}}_{\mathrm{17}}$ -based powders synthesized by mechanically milling and subsequent annealing have been systematically studied. It has been found that a nanoscale 2:17 phase with an average grain size of about 30 nm is developed within the powders, which have an average particle size of about 5 μm. Optimum magnetic properties of $M_s\text{=110.5}$ emu/g, $M_r\text{=66.2}$ emu/g, $M_r{\mathrm{/M}}_s\text{=0.60,}$ $H_c\text{=9.6}$ kOe, and ${\mathrm{(BH)}}_m\text{=10.8}$ MGOe have been obtained in stoichiometric ${\mathrm{Sm}}_{\mathrm{2}}{\mathrm{Co}}_{\mathrm{17}}$ powders milled for 6 h and annealed at $\text{800\hspace{0.05em}°}\mathrm{C}$ for 30 min. The observed magnetic hardening is believed to arise from the high anisotropy of the ${\mathrm{Sm}}_{\mathrm{2}}{\mathrm{Co}}_{\mathrm{17}}$ phase and its nanoscale grain size. A small amount of Zr substitution for Co significantly increases the coercivity by increasing the anisotropy field of the ${\mathrm{Sm}}_{\mathrm{2}}{\mathrm{Co}}_{\mathrm{17}}$ phase. Cu substitution in Zr-contained samples further increases the coercivity by introducing a nanoscale 1:5 phase which forms a uniform mixture with the 2:17 nanograins. The highest coercivity of 20.6 kOe has been obtained in the ${\mathrm{Sm}}_{\mathrm{12}}{\mathrm{(Co}}_{\mathrm{0.92}}{\mathrm{Cu}}_{\mathrm{0.06}}{\mathrm{Zr}}_{\mathrm{0.02}}{\mathrm{)}}_{\mathrm{88}}$ powders. Fe substitution enters the Co lattice sites of the 2:17 structure, leading to an increase of the magnetization but a decrease of the coercivity. An optimum maximum energy product of 14.0 MGOe is obtained in the ${\mathrm{Sm}}_{\mathrm{12}}{\mathrm{(Co}}_{\mathrm{0.7}}{\mathrm{Fe}}_{\mathrm{0.3}}{\mathrm{)}}_{\mathrm{88}}$ powders.