Regensburg 2010 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 21: Magnetic Materials
MA 21.7: Vortrag
Mittwoch, 24. März 2010, 17:00–17:15, H23
Effect of non-magnetic impurities on the ferromagnetism of Mn5Ge3 — •Ivetta Slipukhina1,2, Emmanuel Arras1, Phivos Mavropoulos2, and Pascal Pochet1 — 1Laboratoire de simulation atomistique, SP2M, INAC, CEA, 38054 Grenoble cedex 9, France — 2Institut für Festkörperforschung and Institute for Advanced Simulation, Forschungszentrum Jülich, D-52425 Jülich, Germany
Mn5Ge3 is a ferromagnet with a magnetisation of 2.6 µB/Mn, spin polarisation P0=42% and TC=304 K. Experimentally, interstitial C in this material enhances its ferromagnetic properties and results in essentially increased TC. To understand the nature of exchange interactions in doped Mn5Ge3 and their dependence on the chemistry and concentration of interstitials, we performed first principles electronic structure calculations, utilizing the Korringa-Kohn-Rostoker Green function method within the Coherent-Potential Approximation [1]. The transition temperatures are calculated by means of Monte Carlo method, using a classical Heisenberg Hamiltonian and calculated exchange constants. A non-monotonous variation of the TC with x is found in Mn5Ge3Cx, reflecting the non-monotonous change of the impurity mediated exchange interactions [2]. Strong enhancement of TC is predicted for B- and N-doped Mn5Ge3 [3], making them, along with the Mn5Ge3Cx, promising candidates for spintronics applications.
[1] H. Ebert and R. Zeller, The SPR-TB-KKR package,
http://olymp.cup.uni-muenchen.de/ak/ebert/SPR-TB-KKR.
[2] I. Slipukhina et al., Appl. Phys. Lett. 94, 192505 (2009).
[3] I. Slipukhina, E. Arras, and P. Pochet, in preparation.