Regensburg 2010 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 9: Magnetic Particles, Clusters
MA 9.2: Vortrag
Montag, 22. März 2010, 15:30–15:45, H23
Alloying of Co nanoparticles on differently oriented films and its influence on magnetic properties — •Luyang Han1, Ulf Wiedwald1, Johannes Biskupek2, Ute Kaiser2, and Paul Ziemann1 — 1Institut für Festkörperphysik, Universität Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany — 2Materialwissenschaftliche Elektronenmikroskopie, Universität Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
It has been reported previously [1,2] that ultra-thin Co film deposited on top of a Pt single crystal at elevated temperature will form a Co1−xPtx alloy near the surface. Here, we investigate the local formation of Co1−xPtx alloys starting from a self assembled array of Co nanoparticles (diameter 3 nm and 8 nm) deposited on Pt(001) and Pt(111) films by micellar method [3]. AFM and SEM investigations show a gradual decrease of particle sizes when the particles are annealed above 500 K, while TEM reveals that a few monolayer thick alloy is formed around the particles, whose crystalline orientation is defined by underlying Pt film. The magnetic properties are characterized by means of SQUID magnetometry and XMCD. We observe an increase of both the coercive field and induced Pt magnetic moment after annealing at 570 K. XPS and XMCD reveals a reduced amount of Co after annealing at 770 K, indicating the start of long range diffusion.
[1]S. Ferrer et al., Phys. Rev. B, 56, 9848, (1997)
[2]M. Pan et al., J. Vac. Sci. Technol. A, 23, 790, (2005)
[3]A. Ethirajan et al., Adv. Mater., 19, 406, (2007)