A study on the structural and magnetic properties of 5-nm-thick Co–Pt alloy films grown on thermally oxidized substrates as well as on self-assemblies of spherical particles with sizes down to 10 nm is presented. An out-of-plane easy axis of magnetization was stabilized at deposition temperatures as low as in a broad composition range between 40 and of Pt. Owing to the low deposition temperatures, no chemical long-range order is found. Thus, the strong out-of-plane magnetic anisotropy is expected to be caused by anisotropic short-range order effects. The magnetic behavior of CoPt alloys with an equiatomic composition grown on arrays of particles was found to be similar to those on planar substrates. Structural investigations using high-resolution transmission electron microscopy revealed that a continuous CoPt layer has been formed, covering the particle tops and connecting them. The magnetic CoPt caps exhibit an out-of-plane easy axis for all particle sizes; however, no pronounced difference in coercive field with particle size was observed, which is associated with the specific morphology of the film structure.
Nonepitaxially grown nanopatterned Co–Pt alloys with out-of-plane magnetic anisotropy
D. Makarov, F. Klimenta, S. Fischer, F. Liscio, S. Schulze, M. Hietschold, M. Maret, M. Albrecht; Nonepitaxially grown nanopatterned Co–Pt alloys with out-of-plane magnetic anisotropy. J. Appl. Phys. 1 December 2009; 106 (11): 114322. https://doi.org/10.1063/1.3260243
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