Enhanced magneto-optical Kerr effects in Py/Ag/Bi trilayers

We study the magneto-optical (MO) response of permalloy/silver/bismuth (Py/Ag/Bi) trilayer samples in reference to a control Py film by means of spectroscopic generalized MO ellipsometry. The trilayer structures show enhanced MO Kerr amplitude values compared to optical multilayer calculations based upon the Py film reference measurements, especially in the near-infrared region. This indicates that the optical interference conditions accounted for in the model are not sufficient to explain the influence of the Ag/Bi bilayer in the structure. Instead, the local optical and MO properties of the Py layer itself must be modified by the presence of the Ag/Bi bilayer, which could be caused by enhanced effective spin–orbit coupling.