Nanostructure and magnetic properties of FePt: C cluster films

Yingfan Xu, M. L. Yan, D. J. Sellmyer

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Magnetic properties and nanostructure of FePt: C cluster-deposited films with C volume fraction of 7%, 14%, 33%, and 45% have been studied. As-deposited FePt: C films were prepared by a multilayer method in which FePt layers were deposited from a cluster source employing a gas-aggregation technique and C layers from a normal sputtering gun. In the as-deposited films, FePt clusters with fcc structure are embedded in the C matrix. The high anisotropy FePt L10 cluster structure was realized in the films via post-deposition annealing and the nanostructure of the films was observed by high-resolution transmission electron microscope (TEM). The results for a film with 45 vol. % C showed that FePt clusters are well separated by C matrix and the cluster diameter is about 4.5 nm. The coercivity increases with increase of annealing temperature; coercivities larger than 9 kOe were achieved in the films after annealing at a temperature of 700°C and above. Magnetization reversal of the films was studied by moment-decay measurements and the data were fitted with the Sharrock formula. For the film with 45 vol. % C annealed at 625°C, the thermal stability factor KUV*/kB, T activation volume V*, and anisotropy constant Ku are 231, 0.83 × 101-18cm3 and 1.2 × 107 erg/cm 3, respectively.

Original languageEnglish (US)
Pages (from-to)2525-2527
Number of pages3
JournalIEEE Transactions on Magnetics
Volume40
Issue number4 II
DOIs
StatePublished - Jul 2004

Keywords

  • FePt
  • High anisotropy
  • L1 structure
  • Nanocluster
  • Thermal stability

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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