Structure and composition of iron nanoparticles synthesized using a novel anionic-element complex.

We use a novel solution-based disassociation synthesis scheme of the ionic complex Fe(LiBH4)2 to form Fe nanoparticles. The complex was formed initially using a gentle mechanochemical process, and the Fe nanoparticles emerged after 4 h of ball milling in an air-free environment. Rietveld refinement of x-ray diffraction measurements in an air-free sample holder identified a Im3m α-Fe phase. A room temperature Mössbauer spectrum of the sample presented a six-line spectrum unique to Fe0 metal, and the Fe nanoparticles were extremely well crystallized. Magnetometry results presented a reduced saturation magnetization (e.g., Ms ∼ 85 emu/g at 50 K) that had a Bloch-like T2 temperature dependence, consistent with a gap in the magnon fluctuation spectrum due to finitesize effects. The Fe nanoparticles were magnetically soft, with a coercivity ranging from ∼10 to 20mT with decreasing temperature from 350 K. [ABSTRACT FROM AUTHOR]