Details

Autor(en) / Beteiligte

• White, C. W.
• Withrow, S. P.
• Budai, J. D.
• Thomas, D. K.
• Williams, J. M.
• Meldrum, A.
• Sorge, K. D.
• Thompson, J. R.
• Ownby, G. W.
• Wendelken, J. F.
• Boatner, L. A.

Titel

Annealing-environment effects on the properties of CoPt nanoparticles formed in single-crystal Al2O3 by ion implantation

Ist Teil von

• Journal of applied physics, 2005-12, Vol.98 (11)

Ort / Verlag

United States

Erscheinungsjahr

2005

Quelle

AIP Journals Complete

Beschreibungen/Notizen

• The ion implantation of nearly equal doses of Co and Pt into a single-crystal Al2O3 host followed by thermal annealing leads to the formation of nanoparticles whose phase, structure, and physical properties are strongly dependent on the annealing environment. Annealing in 96%Ar+4%H2 gives rise to ferromagnetic, chemically ordered CoPt nanoparticles with the L10 structure and a magnetic coercivity that can exceed 10kOe at 5K. Annealing in O2 (or in Ar) does not result in the formation of a CoPt alloy. Instead, the implanted Pt precipitates to form oriented elemental Pt nanoparticles, and the implanted Co combines with oxygen to form Co3O4 oxide nanoparticles. Annealing in ultrahigh-vacuum conditions results in a mixture of phases including CoPt3 and Co3O4 and possibly Co. The results obtained for Co+Pt-implanted Al2O3 are compared with the previous results for Fe+Pt-implanted Al2O3 annealed in similar environments.