The preparation of iron complex oxide nanoparticles by pulsed-laser ablation

Nanoparticles of a calcium–iron complex oxide were prepared by pulsed laser ablation on silicon wafer substrates placed at off-axial positions against a target. An ArF excimer laser was used to irradiate a CaFe2O4 target in atmospheres of Ar and O2 at room temperature. The effects of ambient pressure and laser pulse energy on size and composition of nanoparticles were investigated using atomic force microscopy and X-ray photoelectron spectroscopy. The nanoparticles obtained were almost spherical and 2 to 26 nm in diameter. The size distributions of the nanoparticles were very narrow and agreed with the log-normal distribution function. The nanoparticle size increased with ambient pressure and pulse energy. The CarFe atomic ratios in the nanoparticles, however, decreased with increasing ambient pressure and were independent of pulse energy. By this technique, the size and composition of nanoparticles can be easily controlled by laser fluence and pressure during the laser ablation. q1998 Elsevier Science B.V.