Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 32: Postersession II: Spinstruct./Phase Trans. (1-10); Spinelectronics (11-15); Thin Films (16 - 36); Particles/Clusters (37-45); Multiferroics (46-54); Spindynamics/Spin Torque (55 - 76); Post Deadlines (77-79)
MA 32.41: Poster
Freitag, 29. Februar 2008, 11:15–14:00, Poster E
X-ray Absorption Fine Structure analysis of magnetite nanoparticles — •Masataka Kitagami1, Masako Sakamaki1, Takuma Kaneko1, Takehisa Konishi1, Takashi Fujikawa1, Lin Lin2, Jauyn Grace Lin3, and Dimitri Arvanitis4 — 1Chiba University, Chiba, Japan — 2National Changhua University of Education, Changhua, Taiwan — 3National Taiwan University, Taipei, Taiwan — 4Uppsala University, Uppsala, Sweden
Magnetite (Fe3O4) is an important magnetic material for applications, in particular for medicine and biology. The structural, electronic and magnetic state of the near surface region of magnetite nano-particles (of order 2-10 nm) is particularly important in this context. The magnetite nano-particles were characterized in particular, among other techniques, by means of X-ray diffraction, and magnetic susceptometry[1]. Here we present a X-ray Absorption Fine Structure (XAFS) characterization using both soft and hard X-rays at synchrotron radiation laboratories. Soft X-rays allow in particular to assess the nano-particle cleanness and stoichiometry. L-edge Fe XAFS indicates a different electronic state for the Fe atoms in the near surface region for small nanoparticle sizes. The results of the structural hard X-ray XAFS analysis are indicating a different local structure for the nano-particles versus the bulk. In particular Fe K-edge XAFS indicates a octahedrally coordinated Fe atom rich nano-particle surface, in agreement with the Fe L-edge results. [1] K. H. Hsu et al., J. Appl. Phys. 97, 114322 (2005)