Figure 5
From: Engineering optical mode ferromagnetic resonance in FeCoB films with ultrathin Ru insertion
Hysteresis loops along EA and HA direction.
The inset in each panel shows the schematic drawing of Ru atomic layer structure and the magnetic moment orientation in the corresponding sample. A well-defined uniaxial magnetic anisotropy is present in the UMA-FeCoB single layer (a). The trilayers’ hysteresis loops (b–d) are sensitive to the Ru thickness. For the trilayer with Ru thickness tRu = 2 Å (b), hysteresis loops similar to the single layer are observed with slightly larger HC and smaller HK. For the trilayer with 4 Å Ru (c), a double S shape loop along EA direction is present. The upper left inset of (c) shows the hysteresis loop of the trilayer with 4 Å Ru under a wider magnetic field range, indicating that it does not fully saturate even at magnetic fields of 2 kOe. The trilayer with 8 Å Ru (d) shows a lower flip field, implying a weakened interlayer exchange coupling.
