Chemical synthesis and magnetic properties of well-coupled FePt/Fe composite nanotubes.
A simple two-step hydrogen reduction method was used to synthesize FePt/Fe composite nanotubes. As the first step, L1(0) 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 degrees C. 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 degrees C. 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)/Fe(x) 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 phases.
Su
H L
HL
National Laboratory of Solid State Microstructure and Department of Physics, Nanjing University, Nanjing 210093, People's Republic of China.
Tang
S L
SL
Tang
N J
NJ
Wang
R L
RL
Lu
M
M
Du
Y W
YW