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Origin of magnetic anisotropy in doped Ce2Co17 alloys

Liqin Ke, D. A. Kukusta, and Duane D. Johnson
Phys. Rev. B 94, 144429 – Published 21 October 2016
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  • INTRODUCTION
  • CALCULATION DETAILS
  • RESULTS AND DISCUSSION
  • CONCLUSION
  • ACKNOWLEDGMENTS
    • References

    Abstract

    Magnetocrystalline anisotropy (MCA) in doped Ce2Co17 and other competing structures was investigated using density functional theory. We confirmed that the MCA contribution from dumbbell Co sites is very negative. Replacing Co dumbbell atoms with a pair of Fe or Mn atoms greatly enhance the uniaxial anisotropy, which agrees quantitatively with experiment, and this enhancement arises from electronic-structure features near the Fermi level, mostly associated with dumbbell sites. With Co dumbbell atoms replaced by other elements, the variation of anisotropy is generally a collective effect and contributions from other sublattices may change significantly. Moreover, we found that Zr doping promotes the formation of 1-5 structure that exhibits a large uniaxial anisotropy, such that Zr is the most effective element to enhance MCA in this system.

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    • Received 23 August 2016

    DOI:https://doi.org/10.1103/PhysRevB.94.144429

    ©2016 American Physical Society

    Physics Subject Headings (PhySH)

    1. Research Areas
    FerromagnetismMagnetic anisotropySpin-orbit coupling
    Condensed Matter, Materials & Applied Physics

    Authors & Affiliations

    Liqin Ke1,*, D. A. Kukusta1,2, and Duane D. Johnson1,3

    • 1Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, USA
    • 2Institute for Metal Physics, 36 Vernadsky Street, 03142 Kiev, Ukraine
    • 3Departments of Materials Science & Engineering and Physics, Iowa State University, Ames, Iowa 50011-2300

    • *Corresponding author: liqinke@ameslab.gov

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    Issue

    Vol. 94, Iss. 14 — 1 October 2016

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    Images

    • Figure 1
      Figure 1

      Experimental anisotropy fields HA in Ce2TxCo17−x with T=Al [6, 7], Si [6, 8], Ga [6, 9], Zr [10], Hf [10], V [5], Cr [5], Mn [5, 11], Fe [5], and Cu [5].

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    • Figure 2
      Figure 2

      Schematic crystal structures of (a) CeCo5, (b) hexagonal H−Ce2Co17, and (c) rhombohedral R−Ce2Co17. Ce atoms are indicated with large (yellow or magenta colored) spheres. Co atoms are denoted by Wyckoff sites. Dumbbell (red) sites are denoted in H−Ce2Co17 (4f sites) and in R−Ce2Co17 (6c sites), and indicated further by arrows and label. We use larger cells for CeCo5 and R−Ce2Co17 to compare with H−Ce2Co17.

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    • Figure 3
      Figure 3

      Magnetic anisotropy in Ce2T2Co15 and Ce0.66T0.33Co5 with T=Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, and Hf. In Ce2T2Co15, T atoms occupy the dumbbell sublattice. The Ce0.66T0.33Co5 structure was obtained by replacing the pair of dumbbell Co atoms in the original Ce2Co17 with a single T atom. K values derived from experimental HA measurements [5, 11] by using K=12μ0MsHA are also shown.

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    • Figure 4
      Figure 4

      Anisotropy of the scaled onsite SOC energy Kso in Ce2T2Co15 and its contributions from the dumbbell sublattice T(6c) and the rest sublattices.

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    • Figure 5
      Figure 5

      (a) Site-resolved anisotropy of the onsite SOC energy Kso and (b) orbital-resolved Kso(6c) in Ce2Co17−xTx with T=Co, Fe, and Mn.

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    • Figure 6
      Figure 6

      The scalar-relativistic partial density of states projected on the 3d states of T sites in R–Ce2T2Co15 with T=Co, Fe, and Mn. T atoms occupy the dumbbell (6c) sites.

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