Iron-germanium (Fe-Ge) is a complex alloy system that includes several structurally and compositionally diverse phases that exhibit a range of interesting magnetic properties that can change significantly when reduced to nanoscale dimensions. Fe-Ge nanostructures have been synthesized using chemical and physical deposition methods but have not previously been accessible as solution-synthesized colloidal materials. Here, we show that colloidal Fe-Ge nanostructures can be synthesized via the hot injection of an oleylamine solution of Fe(CO)5 into a solution containing GeI4, oleylamine, oleic acid, and hexamethyldisilazane. This approach effectively merges recent advances in the synthesis of colloidal Ge nanocrystals with methods routinely used to synthesize metal and alloy nanoparticles. At 260 C, spherical nanocrystals of Ni2In-type Fe3Ge2 form. Heating the solution at 300 C transforms the spherical Fe 3Ge2 nanocrystals into CoGe-type FeGe nanowires. The Fe3Ge2 nanocrystals are ferromagnetic with Tc ≈ 265 K, whereas the FeGe nanowires are only weakly magnetic.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Materials Chemistry