Characterization of magnetic nanoparticles synthesized ultrafast laser ablation

J. M. J. SANTILLÁN; D. MUÑETÓN; D. F. CORAL; M. B. FERNÁNDEZ VAN RAAP; D. MURACA; D. C. SCHINCA; L. B. SCAFFARDI

Gramado

Congreso; XVI Brazilian Materials Research Society Meeting; 2017

Materials Research Society

Magnetic nanoparticles have attracted much interest due to their broadapplications in magnetic targeting of genes and cells, magnetic hyperthermia,contrast agents for magnetic resonance imaging, drug delivery and remediationof metal pollutants.One of the most active topics in nanotechnology is the synthesis, characterization,and functionalization of magnetic nanoparticles (MNPs). Although MNPfabrication techniques is a wide field, ultrashort pulse laser ablation of solids inliquids has emerged in recent years as a reliable, rapid, and green method forpreparing NPs in suspensions, which are generally spherical in shape.In this work, the optical, magnetic, and structural characteristics of Ni and Fecolloids produced by ultrashort pulsed laser ablation of a solid target were studiedin different liquid media. Optical extinction spectroscopy (OES), micro-Ramanspectroscopy, atomic force microscopy (AFM), transmission electron microscopy(TEM), electron diffraction (ED) and vibrating sample magnetometry (VSM) wereused to yield interrelated information. For the case of Ni, a theoretical analysis ofthe dependence of plasmon resonance of bare core and core-shell Ni NPs with coresize and shell thickness provides insight about core-shell configurations: Ni-NiOand NiO-Ni. For Fe colloids, VSM showed nanoparticles in the superparamagneticstate, while OES revealed an absorption band in the UV region for all liquidsolvents, in contrast to the results obtained with nanosecond lasers. Micro-Ramanspectroscopy showed that the samples were heterogeneous in their composition,with hematite, maghemite, and magnetite nanoparticles in all solvents.