Material parameters and thermal stability of synthetic ferrimagnet free layers in magnetic tunnel junction nanopillars

We have determined the material parameters of optimized synthetic ferrimagnet (SyF) free layers in magnetic tunnel junctions by means of magneto-resistance loops as well as microwave noise spectroscopy under constant voltage, and the field dependence thereof. By comparing the experimental data with calculated loops and spin wave modes from a 2-macrospin model, we have deduced the saturation magnetization, anisotropy, damping, and interlayer exchange coupling. From waiting time experiments of field-induced switching, the energy barrier relevant for the thermally activated switching of the free SyF has been experimentally evaluated and compared to an existing model in order to assess its consistency.