The nanostructure and magnetic properties of Fe69Co31 nanowire arrays with high energy product have been studied. Investigation results revealed a dense and continuous individual nanowire containing a number of defects. After annealing at 550 C, the nanowire arrays had a coercivity of Hc

A simple two-step hydrogen reduction method was used to synthesize FePt/Fe composite nanotubes. As the first step, L10 FePt nanotubes were prepared by heating a porous alumina template loaded with an alcohol solution of a Fe chloride and Pt chloride mixture in flowing hydrogen at 670℃. Then, FePt/Fe composite nanotubes were obtained by reducing the alcohol solution of the Fe chloride within the formed FePt nanotubes at a lower temperature, namely 470℃. Through changing the concentrations of initial alcohol solutions, the FePt:Fe atomic ratios of the composite nanotubes were easily adjusted and the magnetic properties were tuned accordingly. For (FePt)100−x /Fex composite nanotubes with x ranging between 0 and 26 at.%, the hard and soft phases were well coupled and the coercivity was tunable over a large range (1.27-2.73 T). Furthermore, the marked interdiffusion between Fe and FePt, which usually exists in FePt-based composites fabricated by using conventional methods, was not observed in the formed composite nanotubes. This indicates the two-step hydrogen reduction method to be a promising route for synthesizing nanocomposites which are difficult to fabricate by using conventional methods due to the interdiffusion between different phase

r annealing has great dependences on the interpore distance and the wire diameter. The model of the prolate ellipsoid chain modified with the magnetostatic interaction is employed to explain this geometry dependence of the annealing effect. After annealing at 550℃ in H2 atmosphere, good hard magnetic properties (at room temperature, coercivity Hc=3.89 kOe, squareness Mr/Ms=0.954; at 78 K, Hc=4.55 kOe, Mr/Ms=0.954) were obtained in the arrays with a diameter of about 22 nm and an interpore distance of about 50 nm.