Dresden 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 40: Poster II: Bio- and Molecular Magnetism (1-9); Magnetic Coupling Phenomena/Exchange Bias (10-15); Magnetic Particlicles and Clusters (16-29); Micro and Nanostructured Magnetic Materials (30-51); Multiferroics (52-64); Spin Injection in Heterostructures (65-67); Spin-Dyn./Spin-Torque (68-93); Spindependent Transport (94-108)
MA 40.16: Poster
Freitag, 27. März 2009, 11:00–14:00, P1A
Superparamagnetic Switching of Two-dimensional Magnetic Islands Studied by Monte Carlo Simulation — •Thim Stapelfeldt, Elena Y. Vedmedenko, Stefan Krause, Gabriela Herzog, and Roland Wiesendanger — Institut für Angewandte Physik, Universität Hamburg, Jungiusstrasse 11, 20355 Hamburg
Small islands of magnetic material with strong uniaxial anisotropy can be used to store binary information. To maximize the bit density of storage devices consisting of magnetic islands, the size of these islands has to be shrunk as much as possible. A critical bit density is reached, when the islands become so small that they approach the superparamagnetic (SP) limit.
We present a theoretical investigation of the superparamagnetic behavior of two-dimensional Fe/W(110) islands by means of a Monte Carlo simulation based on a single flip Metropolis algorithm. In our simulations the SP region is defined by characteristic temperatures, that indicate the transitions between different magnetic states, i.e. from paramagnetic to SP and from SP to ferromagnetic state. We present the size dependence of the characteristic temperatures, the energy barriers Δ E and attempt frequencies ν0. We compare the energy barriers with energy barriers derived via SP-STM measurements and give a suggestion of the dominating switching mechanism.