We demonstrate a variety of precessional responses of the magnetization to ultrafast optical excitation in nanolayers of Galfenol (Fe,Ga), which is a ferromagnetic material with large saturation magnetization and enhanced magnetostriction. The particular properties of Galfenol, including cubic magnetic anisotropy and weak damping, allow us to detect up to 6 magnon modes in a 120-nm layer, and a single mode with effective damping αeff = 0.005 and frequency up to 100 GHz in a 4-nm layer. This is the highest frequency observed to date in time-resolved experiments with metallic ferromagnets. We predict that detection of magnetization precession approaching THz frequencies should be possible with Galfenol nanolayers.
@article{arxiv.1812.01237,
title = {Optical excitation of single- and multi-mode magnetization precession in Galfenol nanolayers},
author = {A. V. Scherbakov and A. P. Danilov and F. Godejohann and T. L. Linnik and B. A. Glavin and L. A. Shelukhin and D. P. Pattnaik and M. Wang and A. W. Rushforth and D. R. Yakovlev and A. V. Akimov and M. Bayer},
journal= {arXiv preprint arXiv:1812.01237},
year = {2019}
}