Magnetic Alloy Nanoparticles from Laser Ablation in Cyclopentanone and Their Embedding into a Photoresist

Abstract

The generation of nonoxidized magnetic alloy nanoparticles is still a challenge using conventional chemical reduction methods. However, because these nanoparticles are currently attracting much attention, alternative methods are required. In this context, the applicability of femtosecond laser ablation, which has evolved as a powerful tool for the generation of colloidal metal nanoparticles, has been investigated using the example of Ni(48)Fe(52) and Sm(2)Co(17) ablation in cyclopentanone. Besides stability and size measurements, the focus has been placed on the analysis of the elemental composition of nanoparticles, which proved the preservation of the stoichiometry of the target in Ni-Fe nanoparticles but not in Sm-Co. It is assumed that this is due to a greater difference in the heat of evaporation of the bulk alloy components in Sm-Co than in Ni-Fe. Hence, the successful generation of magnetic alloy nanoparticles is possible for alloys composed of elements with similar heats of evaporation. This one-step approach allows the fabrication of nanomagnetic polymer composites (e.g., with application prospects in microtechnology such as microactuators).

Alloying colloidal silver nanoparticles with gold disproportionally controls antibacterial and toxic effects

“…Characterization of NP Laser ablation in liquid provides the production of colloidal nanoparticles from bulk material with a homogeneous composition of elements, in particular if the elements are fully miscible like AgAu, PtIr, or NiFe [32,33,39]. This method permits the generation of functionalized colloids without chemical precursors [44,45].…”

“…Hence, toxicological analysis of laser-generated colloids reveals toxicity only for nanoparticles and not for residual chemicals [28,29], like it is the case with chemically prepared colloids [30,31]. This method enables ablation of different alloy materials, especially if the targets consist of fully miscible elements such as Ag and Au, or Pt and Ir [32][33][34]. The availability of any desired Ag/Au ratio in a solid alloy, in combination with its ablation in liquid by lasers, gives access to colloidal alloy nanoparticles with defined compositions [35,36].…”

Coexistence of plasmonic and magnetic properties in Au89Fe11 nanoalloys

“…48,53,54 Here, the vaporization heats of gold and iron are similar (324 and 340 kJ mol À1 , respectively), but iron can react with oxygen that is dissolved in non-deaerated solvents, as reported for instance during LASiS of NiFe NPs. 55 Transmission electron microscopy (TEM) images of the AuFeNP solution just aer LASiS but prior to the addition of EDTA/PEG indicated the presence of iron oxide and amorphous phases ( Fig. 1D and S1A in the ESI †), likely due to the reaction of ablated Fe atoms with the liquid solution.…”

Process Chain for the Fabrication of Nanoparticle Polymer Composites by Laser Ablation Synthesis

“…Magnetic nanoparticles like Fe-Au [63] or Fe-Ni [55,64] can be used to obtain transparent and/or conducting nanocomposites. Possible applications for such coatings are as a substitute candidate for indium-tin-oxide (ITO) [63] or as a window coating to shield radio frequency electromagnetic waves [55].…”