Iron Oxide Nanocrystals Synthesis by Laser Ablation in Water: Effect of Laser Wavelength

In this research the synthesis of nanocrystalline iron oxides by laser ablation in pure water has been performed by two different wavelengths (first and second harmonics) of high frequency Nd:YAG laser. The obtained results from the X-ray diffraction and transmission electron microscopy analysis of the synthesized samples show the formation of spherical nanocrystalline magnetite with narrow particle size distribution and average diameters of 7 and 17 nm for the samples obtained by first and second harmonics of laser, respectively. According to the hysteresis loops measured by vibrating sample magnetometer, formation of the superparamagnetic nanoparticles (NPs) is confirmed. Investigating the magnetic properties of the two samples indicates a rise in the amount of magnetization of the sample produced by first harmonic of the laser compared to the one produced by the second harmonic wavelength. So it is obtained that the main wavelength of Nd:YAG laser (1,064 nm) results to finer iron oxide NPs with better magnetic properties.