Single crystal iron nanocube synthesis via the surface energy driven growth method

Single crystal iron nanocubes are produced by simply heating a bilayer film. This surface energy driven growth (SEDG) method exploits the difference in surface energies of the components (gamma(Fe) similar to 2.2 J m(-2) versus gamma(Nd) similar to 0.7 J m(-2)) in the binary alloy Fe-Nd system to produce nanocubes of the higher energy Fe component. The dimensions of the cubes range from tens to hundreds of nanometers in size and can be controlled by changing the initial thickness of iron in the deposited Fe-Nd bilayer prior to annealing at 700 degrees C. The composition and structure of the nanocubes was confirmed by transmission electron microscopy analysis as single crystal bcc iron in the alpha-phase. The cubes were found to exist as core-shell structures with the alpha-phase encased by an intermetallic Fe-Nd phase, characteristic of the SEDG growth mechanism.