Hamburg 2001 – wissenschaftliches Programm

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AM: Magnetismus

AM 15: Mikromagnetismus I (Magnetisierungsprozesse und Dom
änenstrukturen)

AM 15.2: Vortrag

Donnerstag, 29. März 2001, 15:15–15:30, S 5.4

Magnetic properties of nanometer-size iron particle arrays — •Steffen Wirth — Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany

Arrays of nanometer-scale iron particles were fabricated by Scanning Tunneling Microscopy assisted chemical vapor deposition. This allowed precise control over the particles dimensions (diameters down to 9 nm) and their arrangement. Magnetic measurements were performed by means of Hall gradiometry and variable field MFM. The temperature dependence of the switching fields of these elongated particles revealed a thermally activated nucleation/propagation type of magnetization reversal even for our smallest particles. These results were supported by angular dependent measurements of the switching fields. Improved high sensitivity Hall magnetometry allowed magnetic viscosity measurements which confirmed an activation volume much smaller than the particle size. The magnetization reversal is discussed within the framework of a phenomenological model.