Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 15: Poster:ThinFilms(1-33),Transp.(34-49),ExchBias(50-56),
Spindynamics(57-70),Micro-nanostr.Mat.(71-82),
Particles/Clust.(83-88), Mag.Imag./Surface(89-96),
Spinelectronics(97-109), Theory/Micromag.(110-116),
Spinstruct/Phasetr.(117-128),Magn.Mat.(129-139),
Aniso.+Measuring(140-145), MolMag.(146-152),
MSMA(153-156)
MA 15.151: Poster
Dienstag, 27. März 2007, 15:00–19:00, Poster A
Magnetic and electronic properties of the transition metal containing polyoxotungstate — •Niklas Damnik1, Manuel Prinz1, Albert Takács4, Jürgen Schnack1, Ulrich Kortz2, Istvan Balasz3, Emil Burzo3, and Manfred Neumann1 — 1Department of Physics, University of Osnabrück, Barbarastraße 7, D-49069 Osnabrück — 2International University Bremen, P.O. Box 750561, D-28725 Bremen — 3Faculty of Physics, Babes-Bolyai University, RO-400084, Cluj-Napoca — 4Physikalisches Institut, Universität Karlsruhe, Wolfgang-Gaede-Straße 1, D-76131 Karlsruhe
New materials based on polyoxometalates (metal-oxygen clusters) are promising stages of development in nano/micro electronic applications that can lead to the emergence of a new technology. Together with X-ray photoelectron spectroscopic (XPS) studies on dimeric Ni-substituted β-Keggin polyoxotungstates K12[{β-GeNi2W10O36(OH)2(H2O)}2]·20 H2O and K12[{β-SiNi2W10O36(OH)2(H2O)}2]·20 H2O magnetic and XPS measurements on the transition metal substituted, dimeric polyoxotungstate [Fe4(H2O)10(β-SbW9O33)2]6− are reported. Magnetic measurements of the salt Cs6[Fe4(H2O)10(β-SbW9O33)2], containing Fe3+ ions, show a magnetization of approximately 10 µB/f.u. at T = 4.2 K and B = 9 T without saturation and were analysed by using an isotropic Heisenberg Hamiltonian. The ground state of the frustrated molecule has a total spin of S = 2. The XPS Fe 2p spectra suggest a 2+ formal valence state indicating that charge-transfer effects are involved.