Time-resolved scanning transmission x-ray microscopy (TR-STXM) has been used for the direct imaging of spin wave dynamics in thin film yttrium iron garnet (YIG) with spatial resolution in the sub 100 nm range. Application of this x-ray transmission technique to single crystalline garnet films was achieved by extracting a lamella (13x5x0.185 μm3) of liquid phase epitaxy grown YIG thin film out of a gadolinium gallium garnet substrate. Spin waves in the sample were measured along the Damon-Eshbach and backward volume directions of propagation at gigahertz frequencies and with wavelengths in a range between 100~nm and 10~μm. The results were compared to theoretical models. Here, the widely used approximate dispersion equation for dipole-exchange spin waves proved to be insufficient for describing the observed Damon-Eshbach type modes. For achieving an accurate description, we made use of the full analytical theory taking mode-hybridization effects into account.
@article{arxiv.1903.00498,
title = {Nanoscale X-Ray Imaging of Spin Dynamics in Yttrium Iron Garnet},
author = {J. Förster and S. Wintz and J. Bailey and S. Finizio and E. Josten and D. Meertens and C. Dubs and D. A. Bozhko and H. Stoll and G. Dieterle and N. Träger and J. Raabe and A. N. Slavin and M. Weigand and J. Gräfe and G. Schütz},
journal= {arXiv preprint arXiv:1903.00498},
year = {2020}
}