Article abstract


Nature Materials 8, 56 - 61 (2009)
Published online: 14 December 2008 | doi:10.1038/nmat2341

Subject Categories: Electronic materials | Magnetic materials

Spin polarization in half-metals probed by femtosecond spin excitation

Georg M. Müller1, Jakob Walowski1, Marija Djordjevic1, Gou-Xing Miao2, Arunava Gupta2, Ana V. Ramos3, Kai Gehrke4, Vasily Moshnyaga4, Konrad Samwer4, Jan Schmalhorst5, Andy Thomas5, Andreas Hütten5, Günter Reiss5, Jagadeesh S. Moodera6 & Markus Münzenberg1


Knowledge of the spin polarization is of fundamental importance for the use of a material in spintronics applications. Here, we used femtosecond optical excitation of half-metals to distinguish between half-metallic and metallic properties. Because the direct energy transfer by Elliot–Yafet scattering is blocked in a half-metal, the demagnetization time is a measure for the degree of half-metallicity. We propose that this characteristic enables us vice versa to establish a novel and fast characterization tool for this highly important material class used in spin-electronic devices. The technique has been applied to a variety of materials where the spin polarization at the Fermi level ranges from 45 to 98%: Ni, Co2MnSi, Fe3O4, La0.66Sr0.33MnO3 and CrO2.

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  1. IV. Phys. Institut, Universität Göttingen, D-37077 Göttingen, Germany
  2. MINT Center, University of Alabama, Tuscaloosa, Alabama 35487, USA
  3. CEA Saclay, 91191 Gif sur Yvette Cedex, France
  4. I. Phys. Institut, Universität Göttingen, D-37077 Göttingen, Germany
  5. Department of Physics, Universität Bielefeld, D-33501 Bielefeld, Germany
  6. Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

Correspondence to: Markus Münzenberg1 e-mail: mmuenze@gwdg.de




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