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

Autor:	S. P. Withrow, James R. Thompson, C. W. White, Alkiviathes Meldrum, K. D. Sorge, J. F. Wendelken, G. W. Ownby, Lynn A. Boatner, J.M. Williams, D. K. Thomas, John D. Budai
Rok vydání:	2005
Předmět:	Materials science Annealing (metallurgy) Metallurgy Alloy Oxide General Physics and Astronomy Nanoparticle engineering.material Coercivity chemistry.chemical_compound Ion implantation Chemical engineering chemistry engineering Magnetic nanoparticles Single crystal
Zdroj:	Journal of Applied Physics. 98:114311
ISSN:	1089-7550 0021-8979
DOI:	10.1063/1.2138801
Popis:	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.
Databáze:	OpenAIRE
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