Magneto-Optical Study of Ultrathin TmIG/Pt Anistropy*

Ferrimagnetic insulator based spintronics has the potential to produce both low-loss technologies as well as next generation skyrmion technologies. TmIG/Pt bilayers have been a great interest for their ability to produce high speed domain walls as well as their ability to be strain and DMI engineered for room temperature skyrmion applications. In order to further the understanding of this system, the sources of anisotropy in the ultrathin film limit must be well understood. In order to overcme the difficulty of low net magnetization and sample, which limits the use of magnetometry below several nanometers of thickness, we employ a highly sensitive magneto-optical technique to study the magnetic anisotropy. We investigate the magnitudes and effects of several contributions to magnetic anisotropy as a function of film thickness.