Regensburg 2007 – scientific programme

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MA: Fachverband Magnetismus

MA 8: Magnetic Materials II

MA 8.4: Talk

Monday, March 26, 2007, 16:00–16:15, H22

Influence of the B2 to L2₁ phase transition on exchange interaction and coercive field in the Co₂MnSi Heusler compound — •Oksana Gaier¹, Jaroslav Hamrle¹, Sebastian Hermsdörfer¹, Burkard Hillebrands¹, Yuya Sakuraba², and Yasuo Ando² — ¹Fachbereich Physik and Forschungsschwerpunkt MINAS, Technische Universität Kaiserslautern, Erwin-Schrödinger-Straße 56, 67663 Kaiserslautern, Germany — ²Department of Applied Physics, Graduate School of Engineering, Tohoku University, Aoba-yama 6-6-05, Aramaki, Aoba-ku, Sendai 980-8579, Japan

It has been shown theoretically that the spin polarization of the Heusler compound Co₂MnSi is very sensitive to the atomic disorder in the crystal lattice. We have investigated the influence of the disorder between Mn and Si sites on the magnetic properties of thin epitaxial Co₂MnSi films with crystal structures varying from B2 to L2₁ phases. The phase transition between B2 and L2₁ was obtained by different annealing temperatures of the sample after its deposition. Brillouin light scattering studies show very small changes of the exchange stiffness constant and the saturation magnetization upon the B2 to L2₁ phase transition. On the other hand, magneto-optical magnetometry reveals that the anisotropy energy gradually decreases when the crystal structure changes from B2 to L2₁.

The work was supported by the DFG in the Research Unit 559 and by the NEDO project 2004IT093 of the Japanese government