Dresden 2014 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 44: Spin Torque and Spin Excitations II
MA 44.3: Vortrag
Donnerstag, 3. April 2014, 15:30–15:45, HSZ 403
Magnons in ultrathin ferromagnetic films with a large perpendicular magnetic anisotropy — •Huajun Qin1, Khalil Zakeri Lori1, Arthur Ernst1, Tzu-Hung Chuang1, Ying-Jiun Chen1, Yang Meng1, and Jürgen Kirschner1,2 — 1Max-Planck-Institut fur Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany — 2Institut fur Physik, Martin-Luther-Universitat Halle-Wittenberg, 06120 Halle, Germany
Ultrathin films with a large perpendicular magnetic anisotropy are of great fundamental as well as technological interest. We present the first experimental observation of high energy magnon excitations in a set of tetragonally distorted ultrathin FeCo films with a large perpendicular magnetic anisotropy. We use spin polarized electron energy loss spectroscopy to excite and probe the magnetic excitations. In this experiment, the polarization vector of the incoming beam is perpendicular to the film magnetization. The magnon dispersion relation and lifetime are probed along the Γ–X direction of the surface Brillouin zone. The magnons possess energies up to 160 meV and lifetimes in the range of a few tens of femtoseconds down to sixteen femtoseconds at the zone boundary. Combined with the first-principles calculations, we show that in addition to the tetragonal distortion, which is the origin of the large perpendicular magnetic anisotropy, the interfacial electronic hybridization also has an impact on the properties of magnons [1].
[1] H.J. Qin, Kh. Zakeri, A. Ernst, T.-H. Chuang, Y.-J. Chen, Y. Meng, and J. Kirschner, PRB 88, 020404 (R) (2013).