Berlin 2008 – scientific programme

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MA: Fachverband Magnetismus

MA 14: Magnetic Half Metals and Oxides

MA 14.4: Talk

Tuesday, February 26, 2008, 11:15–11:30, EB 202

Magnetic anisotropy and exchange interaction in Co₂-based Heusler compounds — •Jaroslav Hamrle¹, Oksana Gaier¹, Burkard Hillebrands¹, Horst Schneider², Gerhard Jakob², Martin Jourdan², Yuya Sakuraba³, Takahide Kubota⁴, Mikihiko Oogane⁴, and Yasuo Ando⁴ — ¹FB Physik and FFSP MINAS, TU Kaiserslautern, Erwin Schrödinger-Str. 56, D-67663 Kaiserslautern, Germany — ²Institut für Physik, Johannes-Gutenberg-Universität, D-55128, Mainz, Germany — ³Institute of Materials Research, Tohoku University, 2-1-1 Katahira, Sendai 980-8577, Japan — ⁴Graduate School of Engineering, Tohoku University, Aoba-yama 6-6-05, Sendai 980-8579, Japan

Co₂-based Heusler compounds are promising candidates to provide 100% spin polarization. We report on magnetic anisotropy, exchange interaction and magnetization reversal in Co₂FeSi, Co₂Cr_0.6Fe_0.4Al (CCFA), Co₂MnSi and Co₂MnAl_xSi_1−x Heusler compounds using Mageto-Optical Kerr effect magnetometry and Brillouin ligh scattering spectroscopy. The samples are studied as a function of sample composition, sample ordering and sample thickness. It is shown that inside ordered CCFA or Co₂FeSi films, there is a wide distribution of the internal field, smearing out the internal 4-fold anisotropy and providing a constant coercive field independent of the sample orientation. The values of the exchange stiffness constant for various Heusler compounds are presented. The project was financially supported by the Research Unit 559 “New materials with high spin polarization” funded by the DFG and by the NEDO Programm 2004/T093.