IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Magnetic Interfaces and Nanostructures Monday Sessions
       Session MI+NS-MoA

Paper MI+NS-MoA6
Greatly Enhanced Magnetic Anisotropies in Pure and Bimetallic Co Nanostructures on Pt(111)

Monday, October 29, 2001, 3:40 pm, Room 110

Session: Nano Magnetics
Presenter: T. Cren, Ecole Polytechnique Federale de Lausanne, Switzerland
Authors: T. Cren, Ecole Polytechnique Federale de Lausanne, Switzerland
S. Rusponi, Ecole Polytechnique Federale de Lausanne, Switzerland
N. Weiss, Ecole Polytechnique Federale de Lausanne, Switzerland
M. Epple, Ecole Polytechnique Federale de Lausanne, Switzerland
H. Brune, Ecole Polytechnique Federale de Lausanne, Switzerland
Correspondent: Click to Email
We report on the enhancement of the magneto-crystalline anisotropy energy K in low dimensional Co islands induced by firm electronic coupling with the underlying Pt(111) substrate. The Co islands were created on Pt(111) using kinetically controlled MBE growth. The correlation between structure and magnetism has been studied by STM and in-situ Surface Magnetic Optical Kerr Effect (SMOKE). We generally observe that the magnetism of the islands is governed by the out-of-plane anisotropy and the M(H)-loops are well described by a two-state Ising model. For pure Co islands, of roughly 1000 atoms size, the shape has only little influence on magnetism (µ=2.2µ@sub B@/atom for ramified and µ=1.9µ@sub B@/atom for compact islands; bulk value 1,7µ@sub B@). From the blocking temperature we deduce an anisotropy energy of K=0.37meV/atom which is greatly enhanced as compared to the Co bulk value of K=0.7µmeV/atom. For double layers islands K is reduced by a factor of two (K=0.16meV/atom) which clearly demonstrates the role of the Co/Pt interface. Finally, we show that the anisotropy can further be enhanced by decoration with Pd or Pt and by bimetallic alloy islands.