Curie Temperature Dependence on Chemical Ordering in FePt and CoPt Nanoparticle

POSTER

Abstract

Current ultra high density recording media utilize the high magnetocrystalline anisotropy of L10 FePt allowing for ferromagnetism down to 3 nm. To use these materials, the media must be heated close to the Curie temperature for a small applied field to switch the particles or grains [1]. The technological requirements for the realization of heat assisted magnetic recording requires a precise understanding of the temperature dependent magnetic properties of FePt and CoPt nanomaterials.
In our work, we report the Curie temperature dependence on chemical ordering in FePt and CoPt nanoparticles. CoPt nanoparticles show a linear relationship between the chemical ordering and Curie temperature, going from 948 K in a disordered sample to 727 K in an ordered L10 sample. FePt showed an opposite behavior with the Curie temperature increasing from 600 K for a disordered sample to 740 K for an ordered L10 sample. The origin of these findings is believed to be related to the change in exchange interactions that occur when the atoms are re-arranged in the lattice transforming from disordered to ordered structures. Current efforts are focused on modeling of the experimental data.

[1] G. Ju et al., IEEE Trans. Magn. 51, 3201709 (2015)

Presenters

  • Frank Abel

    Univ of Delaware, Physics and Astronomy , University of Delaware

Authors

  • Frank Abel

    Univ of Delaware, Physics and Astronomy , University of Delaware

  • Onur Tosun

    Physics and Astronomy , University of Delaware

  • Vasileios tzitzios

    Khalifa University of Science and Technology, Department of Chemical Engineering, Khalifa University of Science and Technology

  • Ralph Skomski

    Nebraska Center for Materials and Nanoscience and Department of Physics and Astronomy, Univ of Nebraska - Lincoln, University of Nebraska, Physics and Astronomy, University of Nebraska

  • David Sellmyer

    University of Nebraska, Nebraska Center for Materials and Nanoscience and Department of Physics and Astronomy, Univ of Nebraska - Lincoln, Physics and Astronomy, University of Nebraska

  • George Hadjipanayis

    Physics and Astronomy , University of Delaware