Anisotropy of Magnetic Moments and Energy in Tetragonal Fe–Co Alloys from First Principles

  • I. Turek
  • J. Kudrnovský
  • K. Carva
Original Paper


Magnetic anisotropies of random body-centered tetragonal Fe–Co alloys are studied by means of relativistic ab initio electronic structure calculations. Special attention is paid to the values and trends of magnetic moments and magnetic anisotropy energies as well as to their sensitivity to current approximations employed. It is found that the high uniaxial anisotropy energy K u, predicted for alloys with 60 % of Co by several authors, is reduced significantly in the coherent potential approximation describing the chemical disorder in real alloys. On the other hand, the four-component Dirac formalism leads to enhanced values of the K u as compared to a simple perturbative treatment of the spin-orbit interaction. Similar behavior is found for the orbital magnetic moments, the values of which are systematically smaller than the measured ones irrespective of the theoretical approach used.


Density functional theory Magnetic anisotropy Fe–Co alloys 



This work was financially supported by the Czech Science Foundation (Grant No. P204/11/1228).


  1. 1.
    Burkert, T., Nordström, L., Eriksson, O., Heinonen, O.: Giant magnetic anisotropy in tetragonal FeCo alloys. Phys. Rev. Lett. 93, 027203 (2004) ADSCrossRefGoogle Scholar
  2. 2.
    Yildiz, F., Luo, F., Tieg, C., Abrudan, R.M., Fu, X.L., Winkelmann, A., Przybylski, M., Kirschner, J.: Strongly enhanced orbital moment by reduced lattice symmetry and varying composition of Fe1−xCox alloy films. Phys. Rev. Lett. 100, 037205 (2008) ADSCrossRefGoogle Scholar
  3. 3.
    Yildiz, F., Przybylski, M., Ma, X.D., Kirschner, J.: Strong perpendicular anisotropy in Fe1−xCox alloy films epitaxially grown on mismatching Pd(001), Ir(001), and Rh(001) substrates. Phys. Rev. B 80, 064415 (2009) ADSCrossRefGoogle Scholar
  4. 4.
    Neise, C., Schönecker, S., Richter, M., Koepernik, K., Eschrig, H.: The effect of chemical disorder on the magnetic anisotropy of strained Fe–Co films. Phys. Status Solidi (b) 248, 2398 (2011) ADSCrossRefGoogle Scholar
  5. 5.
    Bruno, P.: Tight-binding approach to the orbital magnetic moment and magnetocrystalline anisotropy of transition-metal monolayers. Phys. Rev. B 39, 865 (1989) ADSCrossRefGoogle Scholar
  6. 6.
    Turek, I., Drchal, V., Kudrnovský, J., Šob, M., Weinberger, P.: Electronic Structure of Disordered Alloys, Surfaces and Interfaces. Kluwer, Boston (1997) CrossRefGoogle Scholar
  7. 7.
    Vosko, S.H., Wilk, L., Nusair, M.: Accurate spin-dependent electron liquid correlation energies for local spin density calculations: a critical analysis. Can. J. Phys. 58, 1200 (1980) ADSCrossRefGoogle Scholar
  8. 8.
    Shick, A.B., Drchal, V., Kudrnovský, J., Weinberger, P.: Electronic structure and magnetic properties of random alloys: fully relativistic spin-polarized linear muffin-tin-orbital method. Phys. Rev. B 54, 1610 (1996) ADSCrossRefGoogle Scholar
  9. 9.
    Andersen, O.K.: Linear methods in band theory. Phys. Rev. B 12, 3060 (1975) ADSCrossRefGoogle Scholar
  10. 10.
    Turek, I., Drchal, V., Kudrnovský, J.: Relativistic LMTO method for systems of light elements. Philos. Mag. 88, 2787 (2008) ADSCrossRefGoogle Scholar
  11. 11.
    Söderlind, P., Johansson, B., Eriksson, O.: Spin and orbital magnetism in Fe–Co and Co–Ni alloys. J. Magn. Magn. Mater. 104–107, 2037 (1992) CrossRefGoogle Scholar
  12. 12.
    Turek, I., Kudrnovský, J., Drchal, V., Weinberger, P.: Itinerant magnetism of disordered Fe–Co and Ni–Cu alloys in two and three dimensions. Phys. Rev. B 49, 3352 (1994) ADSCrossRefGoogle Scholar
  13. 13.
    Ebert, H.: Fully relativistic band structure calculations for magnetic solids—formalism and application. In: Dreyssé, H. (ed.) Electronic Structure and Physical Properties of Solids, p. 191. Springer, Berlin (2000) CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2012

Authors and Affiliations

  1. 1.Institute of Physics of MaterialsAcademy of Sciences of the Czech RepublicBrnoCzech Republic
  2. 2.Institute of PhysicsAcademy of Sciences of the Czech RepublicPragueCzech Republic
  3. 3.Department of Condensed Matter PhysicsCharles University in PraguePragueCzech Republic

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