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MA: Fachverband Magnetismus
MA 26: Spin Dynamics / Spin Torque IV
MA 26.2: Invited Talk
Thursday, March 25, 2010, 14:30–15:00, H10
Spin dynamics of complex metallic magnets — •Paweł Buczek, Arthur Ernst, and Leonid Sandratskii — Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany
Magnons, often termed as spin-waves, are elementary collective excitations of magnets. Every magnon lowers the magnetization of the system by 2µB, carries energy and crystal momentum. Their signature is found in the inelastic neutron scattering, spin polarized electron energy loss spectroscopy, inelastic scanning tunneling microscopy and spin-resolved two-photon photoemission experiments. Magnons and other magnetic excitation can be one of the coupling mechanisms in high temperature superconductivity. They control the thermodynamics of magnets. Spintronics approaches limits where the magnetic excitations start to interfere with operation of the devices.
In this theoretical talk we will outline an ab-initio method of studying magnetic excitations based on time dependent density functional theory. The method allows to access both the energies and life times of magnons. We will discuss the applications of the method to half-metallic Heusler compounds. In these materials certain decay channels become inoperative for low-energy spin-waves. Next, we will focus on magnons in thin metallic films, where their properties are strongly influenced by the structure of the films and the presence of substrate. Finally, some attention will be paid to the theoretical interpretation of certain novel experiments capable of probing magnons in nanostructures.