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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 54: Poster Session 3
CPP 54.76: Poster
Thursday, April 3, 2014, 15:00–19:00, P2
Characterization of the electronic and magnetic structure of multifunctional NaREF4 (RE = rare earth) core-shell nanoparticles — •Lilli Schneider1, Thorben Rinkel2, Artur Chrobak3, Markus Haase2, and Karsten Küpper1 — 1Physics Department, University of Osnabrück, Germany — 2 Institute of Chemistry, University of Osnabrück, Germany — 3Institute of Physics, University of Silesia, Poland
Rare earth (RE) based nanoparticles of type NaREF4 have attracted lot of attention in the last few years due to their upconverting luminescence. Here, we want to concentrate on electronic and magnetic properties of NaREF4/NaGdF4 nanocrystals, since the magnetic behaviour of these fluorescent nanoparticles are of utmost importance from fundamental and applicative point of view as well. Hexagonal β-phase nanocrystals (3-22 nm) were prepared and characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM).
A detailed study of the electronic structure and magnetic coupling phenomena of the different core-shell nanoparticles is performed using X-ray photoelectron spectroscopy (XPS), magnetometry (SQUID) and X-ray magnetic circular dichroism (XMCD). First SQUID measurements of NaEuF4/NaGdF4 core-shell nanoparticles show butterfly shaped hysteresis loops at low temperature (2 K) in contrast to superparamagnetic behaviour observed for the corresponding "pure" NaEuF4 and NaGdF4 nanoparticles.