Dresden 2009 – wissenschaftliches Programm
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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 40.21: Poster
Freitag, 27. März 2009, 11:00–14:00, P1A
Synthesis and magnetic characterisation of MnAs nanoparticles on GaAs surfaces — •Michael Wolff1, Maria Messing2, Knut Deppert2, and Kornelius Nielsch1 — 1Univ Hamburg, Inst Appl Phys, D-20355 Hamburg, Germany — 2Lund Univ, S-22100 Lund, Sweden
In order to explore the possibility to generate ferromagnetic nanoparticles via annealing of monodisperse aerosol particles, Mn particles are generated in a spark discharge and then, after being sintered and size-selected in an aerosol setup, deposited on (111)B-GaAs substrates. The Mn particles transform into MnAs particles by annealing them under an Arsine background pressure. The reaction takes place in a MOVPE chamber under hydrogen atmosphere. The particle diameter can be controlled and is varied between 15 and 40 nm. While the crystallographic orientation of the Mn particles before annealing is randomly distributed, the crystal structure of the MnAs particles after annealing seems to be determined by the GaAs surface. The magnetic properties are studied using a SQUID magnetometer. The coercive field is expected to depend on the particle diameter and the orientation of the applied field. The substrate's influence on the magnetic properties is investigated by comparing particles on different GaAs surfaces.