Regensburg 2010 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 4: Magnetic Coupling Phenomena/ Exchange Bias
MA 4.6: Vortrag
Montag, 22. März 2010, 12:15–12:30, H22
Magnetic and transport properties of spin-valve elements based on iron oxide nanoparticles — •Giovanni Andrea Badini Confalonieri1, Philipp Szary1, Maria Jose Benitez1,2, Durga Mishra1, Matthias Stadlbauer1, Frank Brüssing1, Matthias Feyen2, Anhui Lu2, Oleg Petracic1, and Hartmut Zabel1 — 1Experimentalphysik IV, Ruhr-Universität Bochum, D-44780 Bochum — 2Max-Planck Institut für Kohlenforschung, D-45470 Mülheim an der Ruhr
Spin-valve elements based on magnetic nanoparticles are prepared by a combination of self-organization, ion etching and thin film growth. Highly monodisperse magnetic iron oxide nanoparticles are prepared by a chemical synthesis route, suspended in a toluene solution and spin coated on a Si substrate to form a well ordered self-assembled hexagonal close-packed monolayer. A Co bias-layer is evaporated on top of the nanoparticles after ion milling. Several cases are investigated: biasing via an unoxidized Co layer or via an exchange bias CoO layer. Surface characterisation is performed by means of Scanning Electron Microscopy and Atomic Force Microscopy. The magnetic characterisation presented includes field-cooling/zero-field cooling M(T) curves and magnetic hysteresis curves, in the temperature range from 15 K to 380 K, as well as surface magnetic properties studies by means of Magneto Optic Kerr Effect and Magnetic Force Microscopy. The transport properties of the spin-valve devices are measured by conventional four-probe technique. The effect of the device geometry on the magnetic and transport properties will be discussed.