Abstract
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. Employing ab initio many-body perturbation theory we studied the magnon spectra of the tetragonal FeCo compounds considering three different experimental ratios, , 1.18, and 1.24 corresponding to FeCo grown on Pd, Ir, and Rh, respectively. We find that for all three cases the short-wavelength magnons are strongly damped and tetragonal distortion gives rise to a significant magnon softening. The magnon stiffness constant decreases almost by a factor of 2 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.
- Received 27 November 2012
DOI:https://doi.org/10.1103/PhysRevB.87.020410
©2013 American Physical Society