Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 18: Poster I : Bio Magn. (1-2); Mag.Imgaging (3-9); Magn. Semiconductors (10-16); Half Metals & Oxides (17-20); Coupl.Phenomena (21-27); Magn. Mat. (28-41); Micro & Nanostr. Magn. Materials (42-61); Micro Magn. (62-64); Surface Magnetism (65-70); Transport Phenomena (71-85)

MA 18.50: Poster

Dienstag, 26. Februar 2008, 15:15–18:30, Poster E

Structure and magnetic properties of iron-platinum particles with iron oxide shell. — •Lubna Basit¹, Ibrahim Shukoor¹, Vadim Ksenofontov¹, Wolfgang Tremel¹, Gerhard H. Fecher¹, Claudia Felser¹, Sergei A. Nepijko², Gerd Schönhense², and Michael Klimenkov³ — ¹Institut of Inorganic and Analytical Chemistry, Johannes Gutenberg - University, 55099 Mainz — ²Institut of Physics, Johannes Gutenberg - University, 55099 Mainz — ³Institut of Materials Research I, Forschungszentrum Karlsruhe, 76021 Karlsruhe

Nanoparticles of solid solution Fe_xPt_1−x, where 0.25≥ x ≥ 0 with Fe₂O₃ shell were synthesized and characterized by high-resolution transmission electron microscopy, energy dispersive X-ray analysis, electron energy loss spectroscopy, Mößbauer spectroscopy and magnetometry. The magnetic properties, of such two-phase particles are interesting because their core is antiferromagnetic or paramagnetic (at very small values of x) whereas the shell is ferrimagnetic. The size of the particles was in the range of several nanometers. ⁵⁷Fe Mößbauer spectroscopy revealed a blocking temperature of about 100 K above which the particles are superparamagnetic. Towards lower temperatures, the magnetic characteristics showed an increase of magnetic rigidity. The saturation magnetization increases by a factor of 1.4 between room temperature and 5 K.