Morphology of Fe / MgO (001) ultrathin films

Autor(en)

Rüdiger Reitinger, Bogdan Sepiol, Gero Vogl, Bastian Pfau, Lorenz-Mathias Stadler, Svetoslav Stankov, Federico Zontone, Nika Spiridis, Jozef Korecki

Abstrakt

The structural and magnetic properties of iron clusters resulting from the evaporation of five

monolayers of iron on a polished MgO(001) substrate are examined by grazing-incidence

small-angle x-ray scattering, and conversion electron Mössbauer spectroscopy. Volmer-Weber growth is observed for room-temperature deposition, giving rise to spherical, superparamagnetic islands. Subsequent annealing causes coarsening and the particles become hemispherical. In the early stages of annealing cluster diffusion takes place, whereas later, Ostwald ripening is the dominant coarsening mechanism. The diffusion coefficient is independent from the crystallographic directions in the MgO(001) surface as it is proven by the isotropic island distribution and shape. The

superparamagnetic state of the particles is conserved during the whole annealing process. For ultrathin iron layers we show that, in contrast to bulk iron, the Curie temperature lies well below room temperature.

Organisation(en)

Dynamik Kondensierter Systeme

Externe Organisation(en)

BESSY GmbH, European Synchrotron Radiation Facility ESRF, Polish Academy of Sciences (PAS), AGH University of Science and Technology

Journal

Journal of Applied Physics

Band

102

Seiten

14536-14542

Anzahl der Seiten

7

ISSN

0021-8979

DOI

https://doi.org/10.1063/1.2760844

Publikationsdatum

2007

Peer-reviewed

Ja

ÖFOS 2012

1030 Physik, Astronomie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/c1ebc3a1-5223-4511-8131-7a61b2ea6448