Regensburg 2013 – scientific programme

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MA: Fachverband Magnetismus

MA 8: Spin Excitations and Spin Torque

MA 8.2: Talk

Monday, March 11, 2013, 09:45–10:00, H23

Strong magnon softening in tetragonal FeCo compounds: An ab initio many-body perturbation theory study — •Ersoy Sasioglu, Christoph Friedrich, and Stefan Blügel — Peter Grünberg Institut and Institute forAdvanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

Magnons play an important role in fast precessional magnetization reversal processes serving as a heat bath for dissipation of the Zeeman energy and thus being responsible for the relaxation of magnetization [1]. Employing ab initio many-body perturbation theory [2] within the framework of the full-potential linearized-augmented plane-wave (FLAPW) method [3], we have studied the magnon spectra of the tetragonal FeCo compounds considering three different experimental c/a ratios, c/a=1.13, 1.18, and 1.24 corresponding to FeCo grown on Pd, Ir, and Rh, respectively. We find that for all three cases the short-wave-length magnons are strongly damped and tetragonal distortion gives rise to a significant magnon softening. The magnon stiffness constant D decreases almost by a factor of two from FeCo/Pd to FeCo/Rh. The combination of soft magnons together with the giant magnetic anisotropy energy suggests FeCo/Rh to be a promising material for perpendicular magnetic recording applications.
K. Baberschke, physica status solidi (b) 245, 174 (2008).
E. Şaşioğlu, A. Schindlmayr, C. Friedrich, F. Freimuth, and S. Blügel, Phys. Rev. B 81, 054434 (2010).
http://www.flapw.de