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MA: Magnetismus
MA 20: Poster:Schichten(1-29),Spintrsp(30-45),Ex-Bias(46-63),Spindyn(64-75),Mikromat.(76-80),Cluster(81-94),Abbv.(95-99),Obflm(100-02),SpElek.(103-09),E-Theo(110-14),Mikromag.(115-16),Spin+PÜ(117-26),Mag.Mat.(127-51),Meth.(152-55),Mol.Mag(156-59),Kondo(160-65
MA 20.91: Poster
Monday, March 7, 2005, 14:00–18:00, Poster TU C
Magnetic property of a weakly interacting nanoparticle system — •Xi Chen1, Subankar Bedanta1, Wolfgang Kleemann1, S. Cardoso2, and P. P. Freitas2 — 1Angewandte Physik, Universität Duisburg-Essen, D-47048 Duisburg, Germany — 2INESC, Rua Alves Redol 9-1, 1000, Lisbon, Portugal
The magnetic property of a weakly interacting nanoparticle system [CoFe(0.7 nm)/Al2O3(3 nm)]10 is investigated by a Superconducting Quantum Interference Device (SQUID) magnetometer. The temperature T dependence of the field cooled magnetization shows a clear increase at low temperature following a simple Curie law, which can be due to the “lost” spins undetectable in Transmission Electron Microscopy (TEM) images. The relaxation curves of the thermoremanent magnetic moment at different temperatures collapse onto one master curve under Tln(t/τ 0) scaling. Aging and memory effects are also observed, which evidence a collective spin glass-like behavior in this nanoparticle system.