Highly crystalline nanospherical iron-platinum systems were produced by 248 nm laser irradiation of a liquid precursor at different laser fluences, ranging from 100-375 mJ/cm(2). The influence of laser intensity on particle size, iron composition, and structure was systematically investigated. Different nanostructures of iron-platinum alloy and chemically disordered iron-platinum L10 phase were obtained without annealing. The prepared precursor solution underwent deep photolysis to polycrystalline iron-platinum nanoalloys through Fe(III) acetylacetonate and Pt(II) acetylacetonate. Fe(II) and Pt(I) acetylacetone decomposed into Fe(0) and Pt(0) nanoparticles. We found that the (001) diffraction peak shifted linearly to a lower angle, with the last peak shifting in opposition to the others. This caused the face-centered cubic L10 structure to change its composition according to laser fluence. The nanostructures were shown to contain iron and platinum only by energy-dispersive spectroscopy at several spots. The response of these iron-platinum nanoparticles to infrared depends on their stoichiometric composition, which is controlled by laser fluence.
Keywords: composition; iron; laser liquid photolysis; nanoparticles; nanostructures; platinum.