Regensburg 2007 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 6: Magnetic Particles/Clusters II

MA 6.5: Vortrag

Montag, 26. März 2007, 16:15–16:30, H10

Kinetics of the ordering transition in FePt nanoparticles — •Michael Müller and Karsten Albe — TU Darmstadt, Institut f"ur Materialwissenschaft, FG Materialmodellierung, Petersenstr. 23, D-64287 Darmstadt

Kinetic Monte Carlo simulations based on an Ising-type lattice Hamiltonian are employed to investigate the kinetics of ordering processes in FePt nanoparticles. In non-supported particles, the A1 to L1_0 transition proceeds with a higher rate in layers at the surace than in the volume of the particles, which demonstrates the important influence of surface diffusion. Because of the statistical nucleation of the ordered phase, however, no single domain particles are obtained and an elimination of the antiphase boundaries can not be observed within the time scales accessible by the simulations. Based on these findings, possibilities for increasing the transition rate in supported nanoparticles are investigated. By systematically modifying interface energetics, surface diffusion can be increased and a preferential ordering direction in the particle can be induced.