Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 70: Supported nanoclusters: Structure, Reactions, Catalysis
O 70.5: Vortrag
Donnerstag, 8. September 2022, 16:15–16:30, H6
Deposition and annealing of FeNi nanoparticles on surfaces — •Mahboobeh Ravankhah1, Mathias Getzlaff1, Gerhard Dehm2, and Philipp Watermeyer2 — 1Institut für Angewandte Physik, Universität Düsseldorf — 2Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf
3d bimetallic nanoparticles have received lots of attention due to their technological applications in ultrahigh density information storage, catalysis and biomedicine. The thermal stability and the magnetic properties of the in-vacuo prepared bimetallic nanoparticles are shown to depend on the composition and their structure. Here we report on new findings of structure and composition of Fe-Ni nanoparticles, synthesized via a magnetron sputtering source and deposited on a Tungsten crystal surface. The elemental distribution of nanoparticles is determined by high resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS). It is found that the nanoparticles have a shell formed by Fe atoms and a core composed of Fe and Ni with the gradient of composition from core to the surface. The melting behavior of nanoparticles was studied under UHV conditions by scanning tunneling microscopy (STM) as a function of heating temperature. The unrolling carpet, surface diffusion and anisotropy spreading are driving processes to form monolayer high islands above the melting point. The relevant result could be helpful for the design and preparation of stable and controllable bimetallic nanoparticles for technological applications.