LOW-TEMPERATURE STABLE NANOMETER-SIZE FCC-FE PARTICLES WITH NO MAGNETIC-ORDERING

Nanometer-size iron particles (approximately 8. nm diameter) with the face-centered-cubic (fcc) structure were made using a technique based on the transversely excited atmospheric CO2-laser-induced breakdown of Fe(CO)5. This fcc gamma-Fe phase is extremely stable based on observations over three years. Mossbauer 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.