Low-temperature stable nanometer-size fcc-Fe particles with no magnetic ordering

Nanometer-size iron particles (∼8 nm diameter) with the face-centered-cubic (fcc) structure were made using a technique based on the transversely excited atmospheric ${\mathrm{CO}}_2$-laser-induced breakdown of Fe(CO${)}_5$. This fcc γ-Fe phase is extremely stable based on observations over three years. Mössbauer spectra over a small velocity range with and without a magnetic field applied show that these nanometer fcc-Fe particles are paramagnets down to a temperature of 1.8 K. This result supports theoretical predictions that the ground state of fcc iron depends strongly on the volume.